Asymmetric synthesis of (2S,3S)- and (2S,3R)-3-prolinomethionines: 3-methylsulfanylmethyl-pyrrolidine-2-carboxylic acids
作者:Philippe Karoyan、Gérard Chassaing
DOI:10.1016/s0957-4166(97)00203-6
日期:1997.6
The synthesis of 3-prolinomethionine can be easily achieved in a diastereoselective and enantioselective way via zinc-enolate cyclisation. After transmetallation by CuCN.2LiCl, the zinc-copper derivative was reacted with S-methyl methanesulfonothioate leading in a ''one-pot'' procedure, to N-(alpha-methylbenzyl)-3-prolinomethionine benzyl ester. The alpha-methylbenzyl group was transformed in vinyl-oxycarbonyl and tertiobutyloxycarbonyl groups successively. Reprotonation of cis Voc prolinomethionine enolate at low temperature yielded the enantiomerically pure trans diastereoisomer. (C) 1997 Elsevier Science Ltd.