Pyrrolidine-5,5-<i>trans</i>-lactams 3. Alternative RegiochemicalOutcome of the Acyl-Iminium Coupling Reaction.
作者:David Andrews、Alan Borthwick、Helene Chaignot、Paul Jones、J. Robinson、Pritom Shah、Martin Slater、Richard Upton
DOI:10.1055/s-2003-40879
日期:2003.8
Enantio- and regioselective syntheses of the pyrrolidine 5,5-trans-lactams benzyl (3aS,6aR)-6,6-dimethyl-5-oxohexahydropyrrolo[3,2-b]pyrrole-1(2H)-carboxylate and benzyl (3aS,6aR)-6S-ethyl-5-oxohexahydropyrrolo[3,2-b]pyrrole-1(2H)-carboxylate from a common intermediate 2-ethoxy-3S-(2,2,2-trifluoro-acetylamino)-pyrrolidine-1-carboxylic acid benzyl ester are reported. The key step in both syntheses is the acyl iminium ion mediated condensation of the pyrrolidine with a ketene acetal.
报道了从共同中间体2-乙氧基-3S-(2,2,2-三氟乙酰氨基)-哌啶-1-羧酸苄酯合成的对映体选择性和区域选择性合成吡咯烷5,5-trans-内酯,分别是苄基(3aS,6aR)-6,6-二甲基-5-氧基六氢吡咯[3,2-b]吡咯-1(2H)-羧酸酯和苄基(3aS,6aR)-6S-乙基-5-氧基六氢吡咯[3,2-b]吡咯-1(2H)-羧酸酯。这两种合成的关键步骤是哌啶与酮烯醇缩合的酰基亚氨离子介导的反应。