The catalytic asymmetric alkylation reaction of α-fluorotetralones promoted by a chiral quaternary ammonium salt derived from cinchonine under phase-transfer catalyzed conditions was described. The reaction proceeded smoothly to give the desired products with up to 91 % ee. This methodology provides a practical protocol for the preparation of optically active fluoro compounds on a large scale.
Thione photochemistry: abstraction and cyclization at the .beta.-position of aralkyl thiones from two excited states
作者:Axel Couture、Jose Gomez、Paul De Mayo
DOI:10.1021/jo00323a008
日期:1981.5
Construction of chiral quaternary carbon centers by asymmetric alkylation of achiral lithium enolates mediated by chiral tetradentate ligands: Stoichiometric and catalytic approaches
作者:Yasuhiro Yamashita、Kazunori Odashima、Kenji Koga
DOI:10.1016/s0040-4039(99)00299-3
日期:1999.4
Enantioselective asymmetric alkylation of achiral lithium enolates mediated by chiral tetradentate amine ligands is achieved to give chiral quaternary carbon centers. Turnover of a chiral tetradentate amine in the presence of an achiral bidentate amine during the reaction is also realized.