Chiral auxiliary control of tacticity in free radical polymerization
作者:Ned A. Porter、Timothy R. Allen、Robert A. Breyer
DOI:10.1021/ja00046a011
日期:1992.9
Chiral oxazolidine acrylamides undergo stereocontrolled free radicalpolymerization. Remarkably high degrees of tacticity have been demonstrated in the polymerization of acrylamides with these chiral auxiliaries that are derived from valine, phenylglycine, and tert-leucine. The polyacrylamides formed in these polymerizations can be converted to poly(acrylic acid), P(AA), and poly(methyl acrylate),
Various fumaric acid diamides were alkylated by reaction with photogenerated radicals. The radicals were produced either by benzophenone triplet hydrogen abstraction (from 1,3-dioxolane, 2-methyl-1,3-dioxolane and adamantane) or via photoinduced electron transfer sensitised by DCN/biphenyl from stannanes (t-BuSnPh3 and Bu4Sn). When chiral substrates were employed the reaction occurred with a good degree of stereoselectivity even when acyclic alkyl radicals were involved. (C) 2000 Elsevier Science Ltd. All rights reserved.
Control of stereochemistry in free radical reactions with oxazolidine auxiliaries
作者:Ned A. Porter、John D. Bruhnke、Wen Xue Wu、Ian J. Rosenstein、Robert A. Breyer
DOI:10.1021/ja00020a066
日期:1991.9
Chiral auxiliary mediated stereoselective allylation of electron deficient radicals
作者:Ian J. Rosenstein、Tina A. Tynan
DOI:10.1016/s0040-4039(98)01884-x
日期:1998.11
Electron deficient radicals bearing oxazolidine chiral auxiliaries undergo efficient addition to allyltributyltin with moderate to excellent stereoselectivities. (C) 1998 Elsevier Science Ltd. All rights reserved.
Asymmetric Iodolactamization Induced by Chiral Oxazolidine Auxiliary
作者:Meihua Shen、Chaozhong Li
DOI:10.1021/jo0488006
日期:2004.11.1
Asymmetric iodolactamization reactions of unsaturated amides with oxazolidines as the chiral auxiliaries were investigated. With (4S)-4-((2R)-2-butyl)-2,2-dimethyloxazolidine as the auxiliary and LiH as the base, a number of unsaturated amides underwent iodolactamization smoothly to afford the corresponding gamma- and delta-lactams in 30-98% yield with de values up to 97%.