Enantioselective alkylation at the α-position of cyclic ketones using a chiral lithium amide as a base in the presence of lithium bromide
作者:Masatoshi Murakata、Makoto Nakajima、Kenji Koga
DOI:10.1039/c39900001657
日期:——
An efficient enantioselectivealkylation reaction at the α-position of cyclicketones (1, 2) can be realized in up to 92% enantiometric excess (e.e.) by first forming their lithium enolates using a chirallithiumamide 4 in the presence of lithiumbromide, followed by treatment with alkyl halides.
Stereoselective Reactions. Part 31: Catalytic Asymmetric Alkylation of Achiral Lithium Enolates Using a Chiral Tetradentate Amine in the Presence of an Achiral Bidentate Amine
作者:Mitsuko Imai、Atsushi Hagihara、Hisashi Kawasaki、Kei Manabe、Kenji Koga
DOI:10.1016/s0040-4020(99)00995-3
日期:2000.1
Catalytic asymmetric alkylation of achiral lithium enolates of 1-tetralone and cyclohexanone with reactive alkyl halides was realized by using a combination of a chiral tetradentate amine (∼0.05 equiv.) and an achiral bidentate amine (2 equiv.).