@article {2116,
	title = {Amine-tethered N-heterocyclic carbene complexes of rhodium(I)},
	journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie},
	volume = {86},
	number = {8},
	year = {2008},
	note = {ISI Document Delivery No.: 329TMTimes Cited: 9Cited Reference Count: 50Jong, Howard Patrick, Brian O. Fryzuk, Michael D.},
	month = {Aug},
	pages = {803-810},
	type = {Article},
	abstract = {A new family of rhodium-diene based complexes has been developed that incorporates an N-heterocyclic carbene ligand with an N-donor tether. The ligand is denoted (Mes)[CNH] 2 (where (Mes)[CNH] is 2,4,6-Me3C6H2NC3H2NCH2CH2NH-2,4,6-Me3C6H2) and (Mes)[CN] for the amido form. The synthesis of the (Mes)[CNH] ligand involves reaction of N-mesitylimidazole with 2-chloroethyl-N-mesitylamine under melt conditions, followed by deprotonation with KN(SiMe3)(2). The reaction of (Mes)[CNH] with [(diene)RhCl](2) results in the formation of the monodentate complexes, (Mes)[CNH]Rh(diene)Cl (where diene = 1,5-cyclooctadiene (COD): 3a; diene = 2,5-norbornadiene (NBD): 3b). Bidentate variants could be isolated as either a neutral species, (Mes)[CN]Rh(diene) 4a-4b, via deprotonation, or an ionic analogue such as [(Mes)[CNH]Rh(diene)]BF4 5a-5b by reaction with NaBF4. Compounds 4-5 are the first examples of rhodium compounds that contained a bidentate NHC ligand with a pendant amino or amido donor. Complexes 3-5 were characterized fully and the solid-state single crystal X-ray structures of 3a, 4a, and 5b are discussed. The utility of these complexes as catalyst precursors for hydrogenation reactions was examined and it was determined that these systems are not significantly more active than colloidal rhodium when parallel reactions were run. Various methods of transfer hydrogenations were also investigated with 3a, which did not yield an appreciable conversion of either benzophenone or N-benzylideneaniline as substrates.},
	keywords = {CATALYSIS, HYDROGENATION, HYDROSILYLATION CATALYSTS, imines, IRIDIUM, KETONES, LIGANDS, N-heterocyclic carbene, REACTIVITY, rhodium, SEARCH, STABLE CARBENES, TRANSFER HYDROGENATION},
	isbn = {0008-4042},
	url = {<Go to ISI>://000257893500010},
	author = {Jong, H. and Patrick, B. O. and Fryzuk,Michael D.}
}
@article {1113,
	title = {Intramolecular C-H and N-H transfer by ruthenium(II) amidophosphine complexes},
	journal = {Organometallics},
	volume = {24},
	number = {22},
	year = {2005},
	note = {ISI Document Delivery No.: 976PNTimes Cited: 6Cited Reference Count: 51},
	month = {Oct},
	pages = {5440-5454},
	type = {Article},
	abstract = {The formation of ruthenium amidophosphine complexes was accomplished by the addition Of [P2N2]Li-2(Diox) (where P2N2 is PhP(CH2SiMe2NSiMe2CH2)(2)PPh and Diox is 1,4-dioxane) to [RuCl2(cod)](x) to generate [P2N2]Ru(cod), or to RuCl2(PPh3)(3) to generate [P2NNH]Ru(C6H4PPh2) In the former complex, the Ru(II) center is in an octahedral environment perched above the P2N2 macrocycle having two formally anionic amido donors; in the latter complex, there is only one amido ligand with the other as an amine donor where the proton originates from the cyclometalated triphenylphosphine group. Reaction of the tridentate amidophosphine ligand precursor [NPN]Li-2(THF)(2) (where NPN is PhP(CH2SiMe2NPh)(2)) with [RuCl2(cod)](x) results in the formation of two diastereomeric complexes of the formula [NPNH]Ru(eta(3):eta(2)-C8H11), wherein the cyclooctadiene ligand has been deprotonated by the ancillary ligand to generate a cyclooctadienyl unit. These Ru(II) complexes are five-coordinate with a bidentate PN ligand and a dangling amine unit. The diastereomers are in equilibrium, as shown by variable-temperature NMR studies. The fluxional process that interconverts diastereomers involves proton transfer from the dangling amine arm to the amido unit, a process that equilibrates the two ends of the tridentate NPN ligand on the chemical time scale. Deprotonation of the amine arm by MN(SiMe3)(2) generates a series of ruthenate complexes of the formula [M(THF)]([NPN]Ru(eta(3):eta(2)-C8H11)), where M = Li or Na. Addition of Me3SiCl results in the formation of new diastereomers that contain silylated dangling arms, and these diastereomers do not interconvert.},
	keywords = {ACTIVATION, AMIDO COMPLEXES, asymmetric, D6 ML5 COMPLEXES, ENANTIOSELECTIVE HYDROGENATION, EXCHANGE-REACTIONS, HYDROGENATION, KETONES, OPPORTUNITIES NOBEL LECTURE, RU-X BOND, STEREOSELECTIVE HYDROGENATION},
	isbn = {0276-7333},
	url = {<Go to ISI>://000232745700031},
	author = {Fryzuk,Michael D. and Petrella, M. J. and Patrick, B. O.}
}
@article {814,
	title = {Enantioselective photochemical synthesis of a simple alkene via the solid state ionic chiral auxiliary approach},
	journal = {Journal of Organic Chemistry},
	volume = {69},
	number = {8},
	year = {2004},
	note = {ISI Document Delivery No.: 811DLTimes Cited: 7Cited Reference Count: 24},
	month = {Apr},
	pages = {2711-2718},
	type = {Article},
	abstract = {Irradiation of cis-bicyclo[4.3.0]non-8-ylacetophenone derivatives (1) in solution and the solid state yields cis-3a,4,5,6,7,7a-hexahydro-1H-indene (2) via a Norrish type II cleavage process. Asymmetric induction studies were conducted by providing the reactants with carboxylic acid substituents to which ionic chiral auxiliaries were attached through salt formation with optically pure amines. Irradiation of the salts (5 in total) in the crystalline state gave enantiomeric excesses of up to 44\%. Single-crystal X-ray diffraction studies were performed on ketone la as well as salts 1d and 1g, and on this basis, the structure-reactivity relationships involved are discussed.},
	keywords = {ELIMINATION, KETONES, PHOTOELIMINATION, REACTIVITY CORRELATIONS, RESOLUTION},
	isbn = {0022-3263},
	url = {<Go to ISI>://000220752500008},
	author = {Chen, S. and Patrick, B. O. and Scheffer, J. R.}
}
@article {848,
	title = {New chiral N,P-oxazolines, and their Ir complexes in asymmetric hydrogenation of an imine},
	journal = {Journal of Molecular Catalysis a-Chemical},
	volume = {224},
	number = {1-2},
	year = {2004},
	note = {ISI Document Delivery No.: 877WSTimes Cited: 8Cited Reference Count: 66},
	month = {Dec},
	pages = {71-79},
	type = {Article},
	abstract = {{(+) (1S.2S)-2-Amino-1-phenyl-13-propanediol reacts with ortho-esters to form 4-hydroxymethyl-5-phenyl-1,3-oxazolines. Subsequent reaction of their toluenesulfonyl derivatives with diphenylphosphinolithium yields the N,P-ligands, (4S,5S)-2-R-4-diphenylphosphinomethyl-5-phenyl- 1.3-oxazoline (R = Me, Et, Ph). X-ray analyses of (4S,5S)-2-methyl-4-toluenesulfonylmethyl-5-phenyl- 1,3-oxazoline and (4S,5S)-2,5-diphenyl-4-diphenylphosphinomethyl-1,3-oxazoline reveal retention of absolute configuration throughout the synthesis. The [Ir(COD)(N,P-oxazoline)]PF6 systems in CH2Cl2 effect catalytic hydrogenation of N-(1 -phenylethylidene)benzylamine},
	keywords = {2-OXAZOLINES, ALLYLIC, ASYMMETRIC HYDROGENATION, CATALYZED ENANTIOSELECTIVE HYDROGENATION, imines, Ir complexes, JM-PHOS LIGANDS, KETONES, LIGANDS, oxazolines, PHOSPHINITE-OXAZOLINE, PHOSPHINOOXAZOLINES, PHOSPHORUS, SEMICORRINS, SUBSTITUTION, TRANSITION-METAL-COMPLEXES, X-ray analysis},
	isbn = {1381-1169},
	url = {<Go to ISI>://000225606300007},
	author = {Ezhova, M. B. and Patrick, B. O. and James, Brian R. and Waller, F. J. and Ford, M. E.}
}
@article {612,
	title = {A formal construction of fasicularin},
	journal = {Organic Letters},
	volume = {5},
	number = {23},
	year = {2003},
	note = {ISI Document Delivery No.: 741QDTimes Cited: 23Cited Reference Count: 42},
	month = {Nov},
	pages = {4313-4316},
	type = {Article},
	abstract = {Our synthetic approach toward fasicularin is presented. Key steps in this construction are a siloxy-epoxide semipinacol rearrangement, a B-alkyl Suzuki reaction and an intramolecular S(N)2 reaction.},
	keywords = {(+/-)-LEPADIFORMINE, CROSS-COUPLING, CYLINDRICINE, DIELS-ALDER REACTION, DIPOLAR CYCLOADDITION, ENANTIOMER, KETONES, MARINE ALKALOID LEPADIFORMINE, NATURAL, reaction, REARRANGEMENT, STEREOSELECTIVE CONSTRUCTION},
	isbn = {1523-7060},
	url = {<Go to ISI>://000186468000019},
	author = {Fenster, M. D. B. and Dake, G. R.}
}
@article {639,
	title = {N-bromosuccinimide promoted ring expansion reactions: Diastereoselective formation of functionalized azaspirocyclic cyclopentanones},
	journal = {Synlett},
	number = {14},
	year = {2003},
	note = {ISI Document Delivery No.: 741GTTimes Cited: 10Cited Reference Count: 30},
	month = {Nov},
	pages = {2131-2134},
	type = {Article},
	abstract = {N-Bromosuccinimide (NBS) induces ring enlargements of 2-(1-hydroxycyclobutyl)-p-toluenesulfonylenamides such as 1. These high yielding reactions typically occur with good diastereoselectivity. This ring expansion protocol under neutral conditions forms compounds that are potentially versatile intermediates for the construction of spirocycle-containing alkaloids.},
	keywords = {bromine, CONSTRUCTION, entry, HALICHLORINE, ION, KETONES, PINNAIC ACID, piperidines, REDUCTION, ring expansion, spiro compounds, SPIROCYCLIC CORE, STEREOSELECTIVE},
	isbn = {0936-5214},
	url = {<Go to ISI>://000186450900005},
	author = {Hurley, P. B. and Dake, G. R.}
}
@article {710,
	title = {Preorganization of achiral molecules for asymmetric synthesis through crystallization-induced immobilization in homochiral conformations},
	journal = {Angewandte Chemie-International Edition},
	volume = {42},
	number = {32},
	year = {2003},
	note = {ISI Document Delivery No.: 716PRTimes Cited: 19Cited Reference Count: 24},
	pages = {3775-3777},
	type = {Article},
	keywords = {asymmetric synthesis, CRYSTAL, crystal engineering, GEOMETRIC REQUIREMENTS, II, INDUCTION, KETONES, PHOTOCHEMICAL-REACTIONS, PHOTOCHEMISTRY, PHOTOCYCLIZATION, reaction, REACTIONS, REACTIVITY, SOLID-STATE, topochemistry},
	isbn = {1433-7851},
	url = {<Go to ISI>://000185038000009},
	author = {Patrick, B. O. and Scheffer, J. R. and Scott, C.}
}
@article {5043,
	title = {A remarkable temperature-dependent, accidental degeneracy of P-31 NMR chemical shifts in Ru(II) diphosphine/diimine complexes},
	journal = {Chemical Communications},
	number = {17},
	year = {2001},
	note = {ISI Document Delivery No.: 469DQTimes Cited: 10Cited Reference Count: 26},
	month = {Sep},
	pages = {1570-1571},
	type = {Article},
	abstract = {Several cis-RUX2((R)-BINAP)(diimine) complexes have been prepared, and many of these exhibit an unusual temperature-dependent, accidental degeneracy of the P-31 shifts in their solution NMR spectra.},
	keywords = {ASYMMETRIC HYDROGENATION, BINAP, CATALYSIS, CHEMISTRY, DERIVATIVES, KETONES, LIGANDS, PHOSPHINE COMPLEXES, REACTIVITY, RUTHENIUM(II) COMPLEXES},
	isbn = {1359-7345},
	url = {<Go to ISI>://000170798800019},
	author = {Cyr, P. W. and Patrick, B. O. and James, Brian R.}
}
@article {4860,
	title = {Nickel bromide as a hydrogen transfer catalyst},
	journal = {Chemical Communications},
	number = {17},
	year = {2000},
	note = {ISI Document Delivery No.: 347EQTimes Cited: 22Cited Reference Count: 25},
	pages = {1647-1648},
	type = {Article},
	abstract = {Catalysed transfer hydrogenation of a range of organics is achieved using NiBr2 in alkaline (PrOH)-Pr-i.},
	keywords = {ACETOPHENONE, ALCOHOLS, ALDEHYDES, ASYMMETRIC TRANSFER HYDROGENATION, COMPLEXES, KETONES, LIGANDS, PROPAN-2-OL, REDUCTION},
	isbn = {1359-7345},
	url = {<Go to ISI>://000088914800044},
	author = {Le Page, M. D. and James, Brian R.}
}
@article {4508,
	title = {Asymmetric induction in the solid state photochemistry of an alpha-mesitylacetophenone derivative through the use of ionic chiral auxiliaries},
	journal = {Tetrahedron Letters},
	volume = {40},
	number = {50},
	year = {1999},
	note = {ISI Document Delivery No.: 258FJTimes Cited: 15Cited Reference Count: 8},
	month = {Dec},
	pages = {8733-8736},
	type = {Article},
	abstract = {Irradiation in the crystalline state of salts formed between alpha-mesitylacetophenone-p-carboxylic acid and a variety of optically pure amines - the so-called {\textquoteright}ionic chiral auxiliary{\textquoteright} approach to asymmetric synthesis - leads to the corresponding 2-indanol in excellent yield and in high enantiomeric excess. X-Ray crystallography reveals the source of the enantioselectivity. (C) 1999 Elsevier Science Ltd. All rights reserved.},
	keywords = {ASYMMETRIC INDUCTION, CARBOXYLATE, CRYSTAL, KETONES, PHOTOCHEMISTRY, REARRANGEMENTS},
	isbn = {0040-4039},
	url = {<Go to ISI>://000083827200004},
	author = {Cheung, E. and Rademacher, K. and Scheffer, J. R. and Trotter, J.}
}
@article {4508,
	title = {Asymmetric induction in the solid state photochemistry of an alpha-mesitylacetophenone derivative through the use of ionic chiral auxiliaries},
	journal = {Tetrahedron Letters},
	volume = {40},
	number = {50},
	year = {1999},
	note = {ISI Document Delivery No.: 258FJTimes Cited: 15Cited Reference Count: 8},
	month = {Dec},
	pages = {8733-8736},
	type = {Article},
	abstract = {Irradiation in the crystalline state of salts formed between alpha-mesitylacetophenone-p-carboxylic acid and a variety of optically pure amines - the so-called {\textquoteright}ionic chiral auxiliary{\textquoteright} approach to asymmetric synthesis - leads to the corresponding 2-indanol in excellent yield and in high enantiomeric excess. X-Ray crystallography reveals the source of the enantioselectivity. (C) 1999 Elsevier Science Ltd. All rights reserved.},
	keywords = {ASYMMETRIC INDUCTION, CARBOXYLATE, CRYSTAL, KETONES, PHOTOCHEMISTRY, REARRANGEMENTS},
	isbn = {0040-4039},
	url = {<Go to ISI>://000083827200004},
	author = {Cheung, E. and Rademacher, K. and Scheffer, J. R. and Trotter, J.}
}
@article {4505,
	title = {An ionic chiral auxiliary-induced regioselective and enantioselective Yang photocyclization reaction in the crystalline state},
	journal = {Tetrahedron Letters},
	volume = {40},
	number = {50},
	year = {1999},
	note = {ISI Document Delivery No.: 258FJTimes Cited: 16Cited Reference Count: 19},
	month = {Dec},
	pages = {8729-8732},
	type = {Article},
	abstract = {cis-9-Decalyl aryl ketones undergo Yang photocyclization in solution to afford an approximately 1:1 mixture of two regioisomeric racemic cyclobutanols. In contrast, irradiation in the crystalline state in the presence of various ionic chiral auxiliaries leads to a single cyclobutanol in >98\% enantiomeric excess. X-Ray crystallography reveals the source of the regio-, diastereo- and enantioselectivity. (C) 1999 Elsevier Science Ltd. All rights reserved.},
	keywords = {ASYMMETRIC INDUCTION, CARBOXYLATE, KETONES, ORGANIC-PHOTOCHEMISTRY, PHOTOCHEMISTRY, SOLID-STATE, Yang photocyclization},
	isbn = {0040-4039},
	url = {<Go to ISI>://000083827200003},
	author = {Cheung, E. and Kang, T. and Raymond, J. R. and Scheffer, J. R. and Trotter, J.}
}
@article {4505,
	title = {An ionic chiral auxiliary-induced regioselective and enantioselective Yang photocyclization reaction in the crystalline state},
	journal = {Tetrahedron Letters},
	volume = {40},
	number = {50},
	year = {1999},
	note = {ISI Document Delivery No.: 258FJTimes Cited: 16Cited Reference Count: 19},
	month = {Dec},
	pages = {8729-8732},
	type = {Article},
	abstract = {cis-9-Decalyl aryl ketones undergo Yang photocyclization in solution to afford an approximately 1:1 mixture of two regioisomeric racemic cyclobutanols. In contrast, irradiation in the crystalline state in the presence of various ionic chiral auxiliaries leads to a single cyclobutanol in >98\% enantiomeric excess. X-Ray crystallography reveals the source of the regio-, diastereo- and enantioselectivity. (C) 1999 Elsevier Science Ltd. All rights reserved.},
	keywords = {ASYMMETRIC INDUCTION, CARBOXYLATE, KETONES, ORGANIC-PHOTOCHEMISTRY, PHOTOCHEMISTRY, SOLID-STATE, Yang photocyclization},
	isbn = {0040-4039},
	url = {<Go to ISI>://000083827200003},
	author = {Cheung, E. and Kang, T. and Raymond, J. R. and Scheffer, J. R. and Trotter, J.}
}
@article {4506,
	title = {Linearly conjugated benzocyclohexadienone photochemistry in the solid state: ionic chiral auxiliary mediated asymmetric induction},
	journal = {Tetrahedron Letters},
	volume = {40},
	number = {50},
	year = {1999},
	note = {ISI Document Delivery No.: 258FJTimes Cited: 16Cited Reference Count: 3},
	month = {Dec},
	pages = {8737-8740},
	type = {Article},
	abstract = {Asymmetric induction in the photochemistry of a linearly conjugated benzocyclohexadienone derivative has been achieved for the first time through the use of the solid state ionic chiral auxiliary method. Enantiomeric excesses as high as 70-80\% at reasonable conversions are readily attainable. Crystal structures for both reactant and product are reported. (C) 1999 Elsevier Science Ltd. All rights reserved.},
	keywords = {ASYMMETRIC INDUCTION, KETONES, PHOTOCHEMISTRY, REARRANGEMENT, [pi(a)(2)+sigma(a)(2)]},
	isbn = {0040-4039},
	url = {<Go to ISI>://000083827200005},
	author = {Cheung, E. and Netherton, M. R. and Scheffer, J. R. and Trotter, J.}
}
@article {4506,
	title = {Linearly conjugated benzocyclohexadienone photochemistry in the solid state: ionic chiral auxiliary mediated asymmetric induction},
	journal = {Tetrahedron Letters},
	volume = {40},
	number = {50},
	year = {1999},
	note = {ISI Document Delivery No.: 258FJTimes Cited: 16Cited Reference Count: 3},
	month = {Dec},
	pages = {8737-8740},
	type = {Article},
	abstract = {Asymmetric induction in the photochemistry of a linearly conjugated benzocyclohexadienone derivative has been achieved for the first time through the use of the solid state ionic chiral auxiliary method. Enantiomeric excesses as high as 70-80\% at reasonable conversions are readily attainable. Crystal structures for both reactant and product are reported. (C) 1999 Elsevier Science Ltd. All rights reserved.},
	keywords = {ASYMMETRIC INDUCTION, KETONES, PHOTOCHEMISTRY, REARRANGEMENT, [pi(a)(2)+sigma(a)(2)]},
	isbn = {0040-4039},
	url = {<Go to ISI>://000083827200005},
	author = {Cheung, E. and Netherton, M. R. and Scheffer, J. R. and Trotter, J.}
}
@article {4573,
	title = {The Norrish type II reaction in the crystalline state: Toward a better understanding of the geometric requirements for gamma-hydrogen atom abstraction},
	journal = {Tetrahedron},
	volume = {55},
	number = {4},
	year = {1999},
	note = {ISI Document Delivery No.: 159BRTimes Cited: 69Cited Reference Count: 58},
	month = {Jan},
	pages = {885-907},
	type = {Article},
	abstract = {By correlating the success or failure of the Norrish type II reaction for a series of compounds in the crystalline state with geometric data derived from X-ray crystallography (the so-called Crystal Structure-Solid State Reactivity Method), the distance and angular requirements for photochemical gamma-hydrogen atom abstraction have been established. These studies indicate that abstractions are preferred when the C=O ... H-gamma, distance is close to the sum of the van der Waals radii of hydrogen and oxygen (2.72 Angstrom), and that the gamma-hydrogen atom can deviate by as much as 50-60 degrees from the plane containing the oxygen n-orbital responsible for abstraction. Because molecular conformations and interatomic distances and angles can be calculated readily by using empirical force field methods, such data permit predictions to be made concerning the outcome of hypothetical Norrish type II processes. (C) 1999 Elsevier Science Ltd. All rights reserved.},
	keywords = {ABSOLUTE ASYMMETRIC-SYNTHESIS, CONFORMATIONAL CONTROL, ENVIRONMENT, KETONES, METHODOLOGY, MOLECULES, PHOTOCHEMISTRY, PHOTOCYCLIZATION, SOLID-STATE, SPECTRA},
	isbn = {0040-4020},
	url = {<Go to ISI>://000078152400001},
	author = {Ihmels, H. and Scheffer, J. R.}
}
@article {4327,
	title = {An investigation of the yang photocyclization reaction in the solid state: Asymmetric induction studies and crystal structure-reactivity relationships},
	journal = {Journal of the American Chemical Society},
	volume = {120},
	number = {49},
	year = {1998},
	note = {ISI Document Delivery No.: 149MWTimes Cited: 101Cited Reference Count: 61},
	month = {Dec},
	pages = {12755-12769},
	type = {Article},
	abstract = {The Norrish/Yang type II photochemistry of 16 ketones having the basic cis-4-tert-butyl-1-benzoylcyclohexane or 2-benzoyladamantane structure has been investigated in the solid state and solution. In both media, ketones bearing methyl substituents alpha to the benzoyl group undergo stereoselective Yang photocyclization to afford endo-arylcyclobutanols. Quantum yield and quenching studies in solution show that the reactions are efficient triplet-mediated processes. Asymmetric induction studies were carried out by providing the reactants with carboxylic acid substituents to which "ionic chiral auxiliaries" were attached through salt formation with optically active amines. Irradiation of the salts (17 in total) in solution gave racemic cyclobutanols, but in the crystalline state, moderate to near-quantitative enantiomeric excesses were obtained. Single crystal X-ray diffraction studies were successfully performed on 10 neutral ketones and four salts. This allowed the reactive gamma-hydrogen atoms to be identified and the distance and angular parameters associated with their abstraction to be tabulated. For the 14 compounds whose crystal structures were determined, the average value of d, the C=O ... H abstraction distance, was 2.61 +/- 0.07 Angstrom, and the values of omega (the gamma-hydrogen out-of-plane angle), Delta (the C=O ... H, angle) and a (the C-H-gamma... O angle) were 53 +/- 11, 84 +/- 7, and 115 +/- 2 degrees, respectively. In a similar manner, the geometric parameters associated with the ring closure reactions of the intermediate 1,4-hydroxy biradicals were estimated from the crystallographic data. This indicates that the biradicals are 66.5 +/- 9.8 and 32.7 +/- 3.2 degrees out of alignment for cleavage, but that they are well oriented for cyclization, with radical separations (D) of 3.08 +/- 0.09 Angstrom. For one of the salts in the adamantane series, the solid-state photoreaction was shown to be topotactic; that is, a single crystal of the reactant salt was transformed quantitatively into a single crystal of the corresponding cyclobutanol salt. Since the absolute configuration of the ionic chiral auxiliary in this case was known, this permitted the absolute steric course of the reaction to be mapped by X-ray crystallography and the abstracted gamma-hydrogen to be identified unequivocally. In addition, the crystal structure of a partially reacted crystal containing 60\% product and 40\% reactant was successfully determined. This showed that the two compounds in the mixed crystal have nearly identical shapes and orientations, thus accounting for the single crystal nature of the process. Finally, it was found that ketones lacking methyl substituents alpha to the benzoyl group an either photochemically unreactive or undergo Norrish type II cleavage. Possible reasons for this difference in behavior are presented and discussed.},
	keywords = {BIRADICALS, CHEMISTRY, CONFORMATIONAL MEMORY, HYDROGEN-ATOM TRANSFERS, II PHOTOPROCESSES, KETONES, ORGANIC-PHOTOCHEMISTRY, PHENYL, POLYMERIZATION, SINGLE-CRYSTAL, TRANSITION STRUCTURES, TRIPLET},
	isbn = {0002-7863},
	url = {<Go to ISI>://000077610100007},
	author = {Leibovitch, M. and Olovsson, G. and Scheffer, J. R. and Trotter, J.}
}
@article {4327,
	title = {An investigation of the yang photocyclization reaction in the solid state: Asymmetric induction studies and crystal structure-reactivity relationships},
	journal = {Journal of the American Chemical Society},
	volume = {120},
	number = {49},
	year = {1998},
	note = {ISI Document Delivery No.: 149MWTimes Cited: 101Cited Reference Count: 61},
	month = {Dec},
	pages = {12755-12769},
	type = {Article},
	abstract = {The Norrish/Yang type II photochemistry of 16 ketones having the basic cis-4-tert-butyl-1-benzoylcyclohexane or 2-benzoyladamantane structure has been investigated in the solid state and solution. In both media, ketones bearing methyl substituents alpha to the benzoyl group undergo stereoselective Yang photocyclization to afford endo-arylcyclobutanols. Quantum yield and quenching studies in solution show that the reactions are efficient triplet-mediated processes. Asymmetric induction studies were carried out by providing the reactants with carboxylic acid substituents to which "ionic chiral auxiliaries" were attached through salt formation with optically active amines. Irradiation of the salts (17 in total) in solution gave racemic cyclobutanols, but in the crystalline state, moderate to near-quantitative enantiomeric excesses were obtained. Single crystal X-ray diffraction studies were successfully performed on 10 neutral ketones and four salts. This allowed the reactive gamma-hydrogen atoms to be identified and the distance and angular parameters associated with their abstraction to be tabulated. For the 14 compounds whose crystal structures were determined, the average value of d, the C=O ... H abstraction distance, was 2.61 +/- 0.07 Angstrom, and the values of omega (the gamma-hydrogen out-of-plane angle), Delta (the C=O ... H, angle) and a (the C-H-gamma... O angle) were 53 +/- 11, 84 +/- 7, and 115 +/- 2 degrees, respectively. In a similar manner, the geometric parameters associated with the ring closure reactions of the intermediate 1,4-hydroxy biradicals were estimated from the crystallographic data. This indicates that the biradicals are 66.5 +/- 9.8 and 32.7 +/- 3.2 degrees out of alignment for cleavage, but that they are well oriented for cyclization, with radical separations (D) of 3.08 +/- 0.09 Angstrom. For one of the salts in the adamantane series, the solid-state photoreaction was shown to be topotactic; that is, a single crystal of the reactant salt was transformed quantitatively into a single crystal of the corresponding cyclobutanol salt. Since the absolute configuration of the ionic chiral auxiliary in this case was known, this permitted the absolute steric course of the reaction to be mapped by X-ray crystallography and the abstracted gamma-hydrogen to be identified unequivocally. In addition, the crystal structure of a partially reacted crystal containing 60\% product and 40\% reactant was successfully determined. This showed that the two compounds in the mixed crystal have nearly identical shapes and orientations, thus accounting for the single crystal nature of the process. Finally, it was found that ketones lacking methyl substituents alpha to the benzoyl group an either photochemically unreactive or undergo Norrish type II cleavage. Possible reasons for this difference in behavior are presented and discussed.},
	keywords = {BIRADICALS, CHEMISTRY, CONFORMATIONAL MEMORY, HYDROGEN-ATOM TRANSFERS, II PHOTOPROCESSES, KETONES, ORGANIC-PHOTOCHEMISTRY, PHENYL, POLYMERIZATION, SINGLE-CRYSTAL, TRANSITION STRUCTURES, TRIPLET},
	isbn = {0002-7863},
	url = {<Go to ISI>://000077610100007},
	author = {Leibovitch, M. and Olovsson, G. and Scheffer, J. R. and Trotter, J.}
}
@article {3740,
	title = {Asymmetric induction in photochemical reactions conducted in zeolites and in the crystalline state},
	journal = {Journal of the American Chemical Society},
	volume = {118},
	number = {5},
	year = {1996},
	note = {ISI Document Delivery No.: TU348Times Cited: 60Cited Reference Count: 17},
	month = {Feb},
	pages = {1219-1220},
	type = {Article},
	keywords = {HYDROGEN ABSTRACTION, KETONES},
	isbn = {0002-7863},
	url = {<Go to ISI>://A1996TU34800044},
	author = {Leibovitch, M. and Olovsson, G. and Sundarababu, G. and Ramamurthy, V. and Scheffer, J. R. and Trotter, J.}
}
@article {3740,
	title = {Asymmetric induction in photochemical reactions conducted in zeolites and in the crystalline state},
	journal = {Journal of the American Chemical Society},
	volume = {118},
	number = {5},
	year = {1996},
	note = {ISI Document Delivery No.: TU348Times Cited: 60Cited Reference Count: 17},
	month = {Feb},
	pages = {1219-1220},
	type = {Article},
	keywords = {HYDROGEN ABSTRACTION, KETONES},
	isbn = {0002-7863},
	url = {<Go to ISI>://A1996TU34800044},
	author = {Leibovitch, M. and Olovsson, G. and Sundarababu, G. and Ramamurthy, V. and Scheffer, J. R. and Trotter, J.}
}
@article {3742,
	title = {On the conformational analysis and photochemical reactivity of 1,6-cyclodecanedione},
	journal = {Molecular Crystals and Liquid Crystals Science and Technology Section a-Molecular Crystals and Liquid Crystals},
	volume = {276},
	year = {1996},
	note = {ISI Document Delivery No.: UJ432Times Cited: 0Cited Reference Count: 2712th International Conference on the Chemistry of the Organic Solid State (ICCOSS XII)JUL 09-14, 1995MATSUYAMA, JAPANMinist Educ, Japan, Ehime Univ, Chem Soc Japan, Soc Synthet Organ Chem, Japan},
	pages = {A289-A298},
	type = {Proceedings Paper},
	abstract = {Photolysis of 1,5-cyclodecanedione, both in the crystalline state and in solution, fails to lead to any Norrish/Yang type II products despite the fact that the conformation of the molecule in the solid state is nearly ideal for hydrogen atom abstraction. Based on X-ray crystal structure and molecular modeling studies, it is argued that gamma-hydrogen abstraction does occur in the solid state, but that closure of the resulting 1,4-biradical is slower than reverse hydrogen atom transfer owing to difficulty in forming the expected 8-membered ring-containing photoproduct. In solution, on the other hand, molecular mechanics calculations indicate that the lack of photoreactivity of 1,5-cyclodecanedione stems from the fact that this molecule exists nearly exclusively in a conformation for which gamma-hydrogen abstraction is sterically impossible.},
	keywords = {ABSTRACTION, C-H...O, II REACTIONS, KETONES, MOLECULAR MECHANICS METHODOLOGY},
	isbn = {1058-725X},
	url = {<Go to ISI>://A1996UJ43200083},
	author = {Lewis, T. J. and Rettig, S. J. and Sauers, R. R. and Scheffer, J. R. and Trotter, J. and Wu, C. H.}
}
@article {3742,
	title = {On the conformational analysis and photochemical reactivity of 1,6-cyclodecanedione},
	journal = {Molecular Crystals and Liquid Crystals Science and Technology Section a-Molecular Crystals and Liquid Crystals},
	volume = {276},
	year = {1996},
	note = {ISI Document Delivery No.: UJ432Times Cited: 0Cited Reference Count: 2712th International Conference on the Chemistry of the Organic Solid State (ICCOSS XII)JUL 09-14, 1995MATSUYAMA, JAPANMinist Educ, Japan, Ehime Univ, Chem Soc Japan, Soc Synthet Organ Chem, Japan},
	pages = {A289-A298},
	type = {Proceedings Paper},
	abstract = {Photolysis of 1,5-cyclodecanedione, both in the crystalline state and in solution, fails to lead to any Norrish/Yang type II products despite the fact that the conformation of the molecule in the solid state is nearly ideal for hydrogen atom abstraction. Based on X-ray crystal structure and molecular modeling studies, it is argued that gamma-hydrogen abstraction does occur in the solid state, but that closure of the resulting 1,4-biradical is slower than reverse hydrogen atom transfer owing to difficulty in forming the expected 8-membered ring-containing photoproduct. In solution, on the other hand, molecular mechanics calculations indicate that the lack of photoreactivity of 1,5-cyclodecanedione stems from the fact that this molecule exists nearly exclusively in a conformation for which gamma-hydrogen abstraction is sterically impossible.},
	keywords = {ABSTRACTION, C-H...O, II REACTIONS, KETONES, MOLECULAR MECHANICS METHODOLOGY},
	isbn = {1058-725X},
	url = {<Go to ISI>://A1996UJ43200083},
	author = {Lewis, T. J. and Rettig, S. J. and Sauers, R. R. and Scheffer, J. R. and Trotter, J. and Wu, C. H.}
}
@article {3675,
	title = {Crystal structure-reactivity relationships in the solid state photochemistry of 2,4,6-triisopropylthiobenzophenone: C=O...H versus C=S...H abstraction geometry},
	journal = {Tetrahedron Letters},
	volume = {37},
	number = {13},
	year = {1996},
	note = {ISI Document Delivery No.: UC590Times Cited: 6Cited Reference Count: 19},
	month = {Mar},
	pages = {2125-2128},
	type = {Article},
	abstract = {X-ray crystal structure solid state photoreactivity correlations are reported for 2,4,6-triisopropylthiobenzophenone (1a) and its p-methoxy derivative 1b. The results reveal interesting differences in the geometry of gamma-hydrogen atom abstraction for ketones and thiones.},
	keywords = {2, 4, 6-TRIISOPROPYLBENZOPHENONES, CONFORMATION, KETONES, PHOTOCYCLIZATION, TRIPLET-STATES},
	isbn = {0040-4039},
	url = {<Go to ISI>://A1996UC59000003},
	author = {Fu, T. Y. and Scheffer, J. R. and Trotter, J.}
}
@article {3675,
	title = {Crystal structure-reactivity relationships in the solid state photochemistry of 2,4,6-triisopropylthiobenzophenone: C=O...H versus C=S...H abstraction geometry},
	journal = {Tetrahedron Letters},
	volume = {37},
	number = {13},
	year = {1996},
	note = {ISI Document Delivery No.: UC590Times Cited: 6Cited Reference Count: 19},
	month = {Mar},
	pages = {2125-2128},
	type = {Article},
	abstract = {X-ray crystal structure solid state photoreactivity correlations are reported for 2,4,6-triisopropylthiobenzophenone (1a) and its p-methoxy derivative 1b. The results reveal interesting differences in the geometry of gamma-hydrogen atom abstraction for ketones and thiones.},
	keywords = {2, 4, 6-TRIISOPROPYLBENZOPHENONES, CONFORMATION, KETONES, PHOTOCYCLIZATION, TRIPLET-STATES},
	isbn = {0040-4039},
	url = {<Go to ISI>://A1996UC59000003},
	author = {Fu, T. Y. and Scheffer, J. R. and Trotter, J.}
}
@article {3678,
	title = {The ionic auxiliary concept in solid state organic photochemistry},
	journal = {Accounts of Chemical Research},
	volume = {29},
	number = {4},
	year = {1996},
	note = {ISI Document Delivery No.: UE738Times Cited: 121Cited Reference Count: 42},
	month = {Apr},
	pages = {203-209},
	type = {Review},
	keywords = {ASYMMETRIC INDUCTION, chirality, CRYSTAL, KETONES, PHOTOREARRANGEMENT, REACTIVITY, SALTS, SUPRAMOLECULAR PHOTOCHEMISTRY},
	isbn = {0001-4842},
	url = {<Go to ISI>://A1996UE73800006},
	author = {Gamlin, J. N. and Jones, R. and Leibovitch, M. and Patrick, B. and Scheffer, J. R. and Trotter, J.}
}
@article {3678,
	title = {The ionic auxiliary concept in solid state organic photochemistry},
	journal = {Accounts of Chemical Research},
	volume = {29},
	number = {4},
	year = {1996},
	note = {ISI Document Delivery No.: UE738Times Cited: 121Cited Reference Count: 42},
	month = {Apr},
	pages = {203-209},
	type = {Review},
	keywords = {ASYMMETRIC INDUCTION, chirality, CRYSTAL, KETONES, PHOTOREARRANGEMENT, REACTIVITY, SALTS, SUPRAMOLECULAR PHOTOCHEMISTRY},
	isbn = {0001-4842},
	url = {<Go to ISI>://A1996UE73800006},
	author = {Gamlin, J. N. and Jones, R. and Leibovitch, M. and Patrick, B. and Scheffer, J. R. and Trotter, J.}
}
@article {2874,
	title = {AN ENANTIOSPECIFIC SYNTHESIS OF 4-METHYLCAMPHOR},
	journal = {Tetrahedron-Asymmetry},
	volume = {4},
	number = {11},
	year = {1993},
	note = {ISI Document Delivery No.: MJ468Times Cited: 10Cited Reference Count: 38},
	month = {Nov},
	pages = {2363-2370},
	type = {Article},
	abstract = {Treatment of (-)-2-methylenebornane (7), derived from (+)-camphor (1), with 45\% HBr /HOAc results in Wagner-Meerwein rearrangement and formation of 4-methylisobornyl bromide (17) in 80-90\% yield. The enantiopurity of (17) was determined by conversion to (+)-4-methylisoborneol (5) and (-)-4-methylcamphor (3).},
	keywords = {CAMPHOR DERIVATIVES, ESTERS, KETONES, NATURAL PRODUCT SYNTHESIS, POTASSIUM, REARRANGEMENTS, ROUTE, STEROID-SYNTHESIS, SYNTHONS},
	isbn = {0957-4166},
	url = {<Go to ISI>://A1993MJ46800024},
	author = {Money, T. and Palme, M. H.}
}
@article {7100,
	title = {PHOTOCHEMISTRY OF MACROCYCLIC KETONES WITHIN ZEOLITES - COMPETITION BETWEEN NORRISH TYPE-I AND TYPE-II REACTIVITY},
	journal = {Tetrahedron Letters},
	volume = {32},
	number = {52},
	year = {1991},
	note = {ISI Document Delivery No.: GX962Times Cited: 9Cited Reference Count: 32},
	month = {Dec},
	pages = {7675-7678},
	type = {Article},
	abstract = {Photolysis of macrocyclic mono- and diketones (1 and 2) included in X and Y zeolites gives Norrish type I products in addition to the products obtained via the Norrish type II process, the only observed process in isotropic media. Enhancement of the type I over the type II process is cation-dependent and especially large enhancements are obtained with Li and Na as cations. The zeolite effect is attributed to a reduction in the rate of the Norrish type II gamma-hydrogen abstraction process.},
	keywords = {ALKANONES, ALKYL, ALPHA-CLEAVAGE, DIBENZYL KETONES, FAUJASITES, KETONES, photolysis, TEMPERATURE-DEPENDENCE},
	isbn = {0040-4039},
	url = {<Go to ISI>://A1991GX96200012},
	author = {Ramamurthy, V. and Lei, X. G. and Turro, N. J. and Lewis, T. J. and Scheffer, J. R.}
}
