@article {1359,
	title = {Structure-reactivity correlations for solid-state enantioselective photochemical reactions established directly from powder X-ray diffraction},
	journal = {Journal of the American Chemical Society},
	volume = {128},
	number = {49},
	year = {2006},
	note = {ISI Document Delivery No.: 113CMTimes Cited: 5Cited Reference Count: 29Cheung, Eugene Y. Harris, Kenneth D. M. Kang, Ting Scheffer, John R. Trotter, James},
	month = {Dec},
	pages = {15554-15555},
	type = {Article},
	keywords = {ASYMMETRIC INDUCTION, CHEMISTRY, CRYSTALLINE STATE, GENETIC ALGORITHM, ORGANIC-PHOTOCHEMISTRY, SALTS},
	isbn = {0002-7863},
	url = {<Go to ISI>://000242575300003},
	author = {Cheung, E. Y. and Harris, K. D. M. and Kang, T. and Scheffer, J. R. and Trotter, J.}
}
@article {1359,
	title = {Structure-reactivity correlations for solid-state enantioselective photochemical reactions established directly from powder X-ray diffraction},
	journal = {Journal of the American Chemical Society},
	volume = {128},
	number = {49},
	year = {2006},
	note = {ISI Document Delivery No.: 113CMTimes Cited: 5Cited Reference Count: 29Cheung, Eugene Y. Harris, Kenneth D. M. Kang, Ting Scheffer, John R. Trotter, James},
	month = {Dec},
	pages = {15554-15555},
	type = {Article},
	keywords = {ASYMMETRIC INDUCTION, CHEMISTRY, CRYSTALLINE STATE, GENETIC ALGORITHM, ORGANIC-PHOTOCHEMISTRY, SALTS},
	isbn = {0002-7863},
	url = {<Go to ISI>://000242575300003},
	author = {Cheung, E. Y. and Harris, K. D. M. and Kang, T. and Scheffer, J. R. and Trotter, J.}
}
@article {1306,
	title = {Orbital-overlap control of the reactivity of a bicyclic 1-hydroxy-1,4-biradical},
	journal = {Angewandte Chemie-International Edition},
	volume = {44},
	number = {32},
	year = {2005},
	note = {ISI Document Delivery No.: 957JYTimes Cited: 13Cited Reference Count: 23},
	pages = {5087-5089},
	type = {Article},
	keywords = {4-BIRADICALS, ASYMMETRIC INDUCTION, asymmetric synthesis, CHIRAL AUXILIARY APPROACH, CONFORMATIONAL MEMORY, ORGANIC-PHOTOCHEMISTRY, PHOTOCHEMICAL-SYNTHESIS, PHOTOCHEMISTRY, radicals, solid-state reactions, STATE REACTIVITY, STEREOSELECTIVITY, structure-activity relationships, TRIPLET 1},
	isbn = {1433-7851},
	url = {<Go to ISI>://000231367300019},
	author = {Yang, C. and Xia, W. J. and Scheffer, J. R. and Botoshansky, M. and Kaftory, M.}
}
@article {5185,
	title = {2000 Alfred Bader Award Lecture - In the footsteps of Pasteur: asymmetric induction in the photochemistry of crystalline ammonium carboxylate salts},
	journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie},
	volume = {79},
	number = {4},
	year = {2001},
	note = {ISI Document Delivery No.: 429PNTimes Cited: 51Cited Reference Count: 52},
	month = {Apr},
	pages = {349-357},
	type = {Article},
	abstract = {This review describes the development of a new, synthetically useful method of asymmetric synthesis in organic photochemistry. Similar in many ways to the Pasteur procedure for resolving racemic carboxylic acids and organic amines, the method relies on the use of crystalline organic salts in which the enantioselectivity of a photochemical reaction of an achiral organic ion (for example, a carboxylate anion) is governed in the solid state by the presence of an optically pure counterion (for example, an optically active ammonium ion). Such optically pure counterions are termed ionic chiral auxiliaries. Salts containing ionic chiral auxiliaries are required to crystallize in chiral space groups, which provide the asymmetric environment necessary for chiral induction. Using this methodology, we have obtained near-quantitative optical yields in a wide variety of photochemical reactions.},
	keywords = {ABSOLUTE-CONFIGURATION CORRELATION, ACID-DERIVATIVES, asymmetric synthesis, chiral auxiliaries, crystal structure-reactivity relationships, di-pi-methane, GEOMETRIC REQUIREMENTS, II REACTION, ionic chiral auxiliaries, ORGANIC-PHOTOCHEMISTRY, PHOTOCHEMISTRY, solid state, SOLID-STATE PHOTOCHEMISTRY, STRUCTURE-REACTIVITY RELATIONSHIPS, YANG PHOTOCYCLIZATION REACTION},
	isbn = {0008-4042},
	url = {<Go to ISI>://000168526300001},
	author = {Scheffer, J. R.}
}
@article {5101,
	title = {An unexpected Paterno-Buchi reaction in the crystalline state},
	journal = {Organic Letters},
	volume = {3},
	number = {21},
	year = {2001},
	note = {ISI Document Delivery No.: 484UMTimes Cited: 6Cited Reference Count: 43},
	month = {Oct},
	pages = {3361-3364},
	type = {Article},
	abstract = {[GRAPHICS] The solution and solid-state photochemistry of a series of aryl 1-phenylcyclopentyl ketones (1) was investigated. While typical Norrish type I products were formed in solution, irradiation of crystals of I afforded the novel oxetanes 3 and 4 regiospecifically. The formation of the oxetanes is believed to occur through Norrish type I cleavage and hydrogen abstraction, producing an alkene and an aldehyde, followed by a Paternb-BUchi reaction within the crystal lattice cage.},
	keywords = {ASYMMETRIC INDUCTION, ORGANIC-PHOTOCHEMISTRY, PHOTOCYCLOADDITION, SALTS, SOLID-STATE, YANG PHOTOCYCLIZATION REACTION},
	isbn = {1523-7060},
	url = {<Go to ISI>://000171708000034},
	author = {Kang, T. and Scheffer, J. R.}
}
@article {4572,
	title = {11,12-bis(diethylaminomethyl)-9,10-dihydro-9,10-ethenoanthracene: A probe for the heavy atom effect in solid state photoreactions},
	journal = {Tetrahedron},
	volume = {55},
	number = {8},
	year = {1999},
	note = {ISI Document Delivery No.: 167FYTimes Cited: 2Cited Reference Count: 26},
	month = {Feb},
	pages = {2171-2182},
	type = {Article},
	abstract = {The photochemistry of title compound 2 and its hydrogen halide salts was investigated in solution and in the solid state. In the solid state the halide ions were shown to cause a heavy atom effect that was not observed in solution. The orientation of the halide ions towards the chromophore was determined on the basis of the corresponding structures in the solid state as determined by X-ray crystallography. (C) 1999 Elsevier Science Ltd. All rights reserved.},
	keywords = {CRYSTALLINE, MOLECULES, ORGANIC-PHOTOCHEMISTRY, REACTIVITY, SALTS},
	isbn = {0040-4020},
	url = {<Go to ISI>://000078622900004},
	author = {Ihmels, H. and Patrick, B. O. and Scheffer, J. R. and Trotter, J.}
}
@article {4572,
	title = {11,12-bis(diethylaminomethyl)-9,10-dihydro-9,10-ethenoanthracene: A probe for the heavy atom effect in solid state photoreactions},
	journal = {Tetrahedron},
	volume = {55},
	number = {8},
	year = {1999},
	note = {ISI Document Delivery No.: 167FYTimes Cited: 2Cited Reference Count: 26},
	month = {Feb},
	pages = {2171-2182},
	type = {Article},
	abstract = {The photochemistry of title compound 2 and its hydrogen halide salts was investigated in solution and in the solid state. In the solid state the halide ions were shown to cause a heavy atom effect that was not observed in solution. The orientation of the halide ions towards the chromophore was determined on the basis of the corresponding structures in the solid state as determined by X-ray crystallography. (C) 1999 Elsevier Science Ltd. All rights reserved.},
	keywords = {CRYSTALLINE, MOLECULES, ORGANIC-PHOTOCHEMISTRY, REACTIVITY, SALTS},
	isbn = {0040-4020},
	url = {<Go to ISI>://000078622900004},
	author = {Ihmels, H. and Patrick, B. O. 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 {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.}
}
