@article {2528, title = {Synthesis and Characterization of a New Thiophene-Bridged Diamidophosphine [NPN] Donor Set and Its Coordination Chemistry with Zirconium(IV): Unexpected Deprotonation-Lithiation Sequence with a Mesitylaminothiophene Precursor}, journal = {Organometallics}, volume = {28}, number = {17}, year = {2009}, note = {ISI Document Delivery No.: 489MMTimes Cited: 1Cited Reference Count: 43Menard, Gabriel Jong, Howard Fryzuk, Michael D.}, month = {Sep}, pages = {5253-5260}, type = {Article}, abstract = {The synthesis and characterization of the thiophene-bridged diamidophosphine proligand [NPN]H-S(2) (2) (where [NPN]H-S(2) = {[N-(2,4,6-Me3C6H2)(3-NH-SC4H2-2-)](2)PPh}) along with several [NPN](ZrX2)-Zr-S (X = NMe2, Cl, I) complexes are presented. The ligand precursor [NPN]H-S(2) was prepared from N-(2,4,6-Me3C6H2)(3-NH-4-Br-SC4H2) (1),(BuLi)-Bu-t, and PhPCl2 in Et2O in 50\% yield; the stereochemistry of the ligand precursor was unexpected and likely resulted from a competitive bromine-lithium exchange and deprotonation sequence with the thiophene starting material I and (BuLi)-Bu-t. A mechanism to rationalize the observed stercochemistry of the product is proposed following deuteration experiments. [NPN]Zr-S(NMe2)(2) (8) can be prepared in 80\% yield by the direct reaction of [NPN]H-S(2) and Zr(NMe2)(4) in toluene. Both [NPN](ZrCl2)-Zr-S (9) and [NPN](ZrI2)-Zr-S (10) are prepared in high yield by the reaction of 8 with excess Me3SiCl or Me3SiI, respectively.}, keywords = {DIARYLAMIDO-PHOSPHINE-LIGANDS, DIRECTED ORTHO-LITHIATION, END-ON, hafnium, HALOGEN EXCHANGE, lithium, METAL-COMPLEXES, MOLECULAR NITROGEN, ON-BOUND DINITROGEN, PALLADIUM-CATALYZED AMINATION, SIDE-ON}, isbn = {0276-7333}, url = {://000269424200046}, author = {Menard, G. and Jong, H. and Fryzuk,Michael D.} } @article {483, title = {Studies toward the synthesis of contignasterol: Functionalization of the steroidal A,B ring system}, journal = {Synthetic Communications}, volume = {32}, number = {19}, year = {2002}, note = {ISI Document Delivery No.: 595TJTimes Cited: 2Cited Reference Count: 12}, pages = {2991-3002}, type = {Article}, abstract = {The synthesis of androstane-3alpha,4beta,6alpha,7beta-tetrol-17-one (2), a potentially key intermediate for the preparation of contignasterol (1), was achieved by functionalization of the A,B-ring portion or the readily available androst-4-ene-3,17-dione (3).}, keywords = {EPOXIDATION, lithium, ring opening, stereoselective reduction, steroid}, isbn = {0039-7911}, url = {://000178124600011}, author = {Rogers, C. and Shen, Y. P. and Burgoyne, D. and Piers, E.} } @article {5078, title = {Synthesis, structure, and reactivity of diamidophosphine complexes of yttrium and the lanthanides}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {79}, number = {7}, year = {2001}, note = {ISI Document Delivery No.: 473RETimes Cited: 10Cited Reference Count: 17}, month = {Jul}, pages = {1194-1200}, type = {Article}, abstract = {The reaction of the dilithiodiamidophosphine ligand precursor PhP(CH2SiMe2NPh)(2)Li-2(THF)(2)([NPN]Li-2(THF)(2)) with LnCl(3)(THF)(3) (Ln = Y, Sm, Ho. Yb. Lu; THF = tetrahydrofuran) in refluxing toluene generates the mononuclear complexes [NPN]LnCI(THF) in good yield. The molecular structures have been shown to be five-coordinate in the solid state and in solution. Attempts to prepare alkyl derivatives have only met with partial success; the reaction of MeMgCl with [NPN]YCl(THF) generates the partially characterized mixed-metal derivative [NPN]YMe2MgCl. The reaction with LiAlH4 results in complete ligand exchange and the formation of the tetranuclear lithium aluminum hydride derivative ([NPN]AlH2Li(THF))(2). Reduction of the lutetium derivative with KC8 and naphthalene generated the dinuclear naphthalene-bridged species {[NPN]Lu}(2)(mu-eta (4):eta (4)-C10H8) wherein each Lu centre engages in eta (4)-coordination to opposite sides of the arene moiety. X-ray crystallography was used to characterize the four complexes.}, keywords = {aluminum, BRIDGING N-2 UNIT, CATALYSTS, CRYSTAL-STRUCTURE, DINITROGEN, F-BLOCK METALS, lanthanides, LIGAND, lithium, mixed-donor ligands, NAPHTHALENE, OLEFIN POLYMERIZATION, SIDE-ON, TERTIARY PHOSPHINE COMPLEXES, YTTRIUM}, isbn = {0008-4042}, url = {://000171061200016}, author = {Fryzuk,Michael D. and Yu, P. H. and Patrick, B. O.} } @article {4052, title = {The versatility of lithium reagents in synthetic organometallic chemistry: Their differing reactions with [(CpMo)-Mo-*(NO)(CH2SiMe3)(2)]}, journal = {Chemistry-a European Journal}, volume = {3}, number = {10}, year = {1997}, note = {ISI Document Delivery No.: YA856Times Cited: 13Cited Reference Count: 44}, month = {Oct}, pages = {1579-1587}, type = {Article}, abstract = {[Cp*Mo(NO)(CH2SiMe3)(2)] exhibits three principal types of reaction with the various lithium reagents investigated during this study, namely: regioselective deprotonation, reduction, and addition. Deprotonation of the reactant, achieved by treatment with lithium amide reagents, leads ultimately to the formation of the alkylidene {\textquoteright}{\textquoteright}ate{\textquoteright}{\textquoteright} complex [Cp*Mo(NO)(CH2SiMe3)(=CHSiMe3)](2)[Li-2(thf)(3)] (1). While LiN(SiMe3)(2) effects this conversion directly with no detectable intermediates, reaction with 1 equiv of LDA in THF for 15 min deprotonates the Cp* ligand to form the lithium salt of the {\textquoteright}{\textquoteright}tucked-in{\textquoteright}{\textquoteright} ate complex [(eta(5),eta(1)C(5)Me(4)CH(2))Mo(NO)(CH2SiMe3)(2)][Li(thf)(3)] (2) in 40\% isolated yield, Complex 2 slowly converts to the thermodynamically more stable 1 when left as a THF or C6D6 solution at ambient temperature fbr 48 h. Reaction of the dialkyl starting material with either tBuLi or PhLi leads to the production of the alkylidene complex 1 in irreproducible yields (10-50\% NMR; not isolable). A kinetic analysis of the reaction of [Cp*Mo(NO)(CH2SiMe3)(2)] with LiN(SiMe3)(2) indicated that the reaction was first-order in both the lithium and molybdenum reagents, and the activation parameters of Delta H-double dagger = 7,3 +/- 1.0 kcal mol(-1) and Delta S (double dagger) = -34 +/- 3 e.u. suggest an associative process. Treatment of the neutral dialkyl with 1 equiv of LiPPh2, in THF results in a one-electron reduction and production of {[Cp*Mo(NO)(CH2SiMe3)(2)][Li(thf)]}(2) (3). If left in solution, the 17e(-) dialkyl anion 3 is converted to the 18e(-) alkylidene anion 1 by the Ph2P-PPh2 coproduct, which effects the requisite hydrogen-atom abstraction. Finally, addition of a sterically undemanding alkyllithium reagent such as MeLi to the 16e(-) dialkyl reactant leads to the formation of the 18e(-) trialkyl anionic complex [Cp*Mo(NO)(CH2SiMe3)(2)(Me)][Li(thf)(3)] (4). Warming of 4 in a C6D6 solution results in loss of methane and production of 1. In most cases, the chemistry exhibited by the Mo system is duplicated by the analogous W congener, [Cp*W(NO)(CH2SiMe3)(2)]. The solid-state molecular structures of complexes 1 and 4 have been established by single-crystal X-ray crystallographic analyses.}, keywords = {COMPLEXES, H BOND ACTIVATION, LIGAND, lithium, LIVING POLYMERIZATION, {ALKYLIDENE COMPLEXES}, isbn = {0947-6539}, url = {://A1997YA85600004}, author = {Legzdins,Peter and Sayers, S. F.} } @article {3739, title = {Novel synthetic routes to the anionic alkylidene complex [Cp*Mo(NO)(CH(2)SiMe(3))(=CHSiMe(3))](-) from its neutral dialkyl precursor}, journal = {Organometallics}, volume = {15}, number = {19}, year = {1996}, note = {ISI Document Delivery No.: VH293Times Cited: 13Cited Reference Count: 38}, month = {Sep}, pages = {3907-3909}, type = {Article}, abstract = {Conversion of the dialkyl nitrosyl complex Cp*Mo(NO)(CH(2)SiMe(3))(2) (1) to the lithium salt of the anionic alkylidene complex [Cp*Mo(NO)(CH(2)SiMe(3))(=CHSiMe(3))](2)[Li-2(THF)(3)] (2) may be effected with each of the lithium reagents LiN(SiMe(3))(2), LDA, or LiPPh(2). Interestingly, each transformation follows a different mechanistic pathway.}, keywords = {DERIVATIVES, H BOND ACTIVATION, LIGAND, lithium, {DECOMPOSITION}, isbn = {0276-7333}, url = {://A1996VH29300002}, author = {Legzdins,Peter and Sayers, S. F.} } @article {2951, title = {SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF (NEOPENTYL)(OCTAETHYLPORPHYRINATO)RUTHENIUM COMPLEXES, INCLUDING [RU(OEP)NP]2(MU-LI)2}, journal = {Organometallics}, volume = {13}, number = {7}, year = {1994}, note = {ISI Document Delivery No.: NW037Times Cited: 21Cited Reference Count: 26}, month = {Jul}, pages = {2542-2544}, type = {Note}, abstract = {Reaction of neopentyllithium (LiNp) with the octaethylporphyrin complex Ru(OEP)Cl2 yields Ru-(OEP)Np (1), which can be treated with further LiNp to give [Ru(OEP)Np]2(mu-Li)2 (2). The structures of 1 (the first for an iron-group metalloporphyrin alkyl) and the more remarkable 2, revealing two Li atoms sandwiched between metalloporphyrin moieties, are determined.}, keywords = {CHEMISTRY, CRYSTAL-STRUCTURE, DIMERS, lithium, OXIDATION, REACTIVITY, REDOX, TETRAVALENT RUTHENIUM PORPHYRIN}, isbn = {0276-7333}, url = {://A1994NW03700002}, author = {Alexander, C. S. and Rettig, S. J. and James, Brian R.} }