Total Synthesis of (−)-α-Kainic Acid by (−)-Sparteine-Mediated Asymmetric Deprotonation−Cycloalkylation
作者:M. Montserrat Martinez、Dieter Hoppe
DOI:10.1021/ol0485666
日期:2004.10.1
[reaction: see text] We report a new enantioselective synthesis of (-)-alpha-kainic acid from d-serine methyl ester hydrochloride, based on a (-)-sparteine-mediated asymmetric deprotonation of an intermediate carbamate that, by stereospecific anti S(N)'S(E)' intramolecular cycloalkylation, leads to the pyrrolidine ring precursor of (-)-alpha-kainic acid, in high yield and diastereoselectivity. The
Novel Approach to the (-)-Sparteine-Mediated Synthesis of Kainoids:Total Synthesis of (-)-α-Kainic Acid by (-)-Sparteine-Mediated Deprotonation
作者:M. Montserrat Martínez、Dieter Hoppe
DOI:10.1002/ejoc.200400824
日期:2005.4
We report a new synthesis of kainoids via allyllithium compounds using an intramolecular cycloalkylation as the key step. Preparation of different substituted pyrrolidines was carried out by using carbamates, that react with the chiral base n-BuLi/(–)-sparteine with strong selection between the diastereotopic protons adjacent to the carbamate group in favour for the pro-S proton. (–)-α-Kainic acid was