烯丙醇在Re 2 O 7的存在下进行转座反应,从而可以通过用一种亲电亲和剂捕获一种异构体来控制平衡。当捕获基团是醛或酮时,可能会发生其他电离,从而导致形成环氧碳鎓离子。通过将双分子亲核加成至中间物来终止该过程,为合成各种含氧杂环化合物提供了一种通用的方法。了解序列中各步骤的相对速率会导致设计反应,从而创建多个具有良好至极佳控制水平的立体中心。
Boronic Acid Catalysis as a Mild and Versatile Strategy for Direct Carbo- and Heterocyclizations of Free Allylic Alcohols
作者:Hongchao Zheng、Sina Ghanbari、Shinji Nakamura、Dennis G. Hall
DOI:10.1002/anie.201201620
日期:2012.6.18
BAC to the future: Boronic acid catalysis (BAC) was applied to the direct activation of alcohols leading to the preparation of carbocycles (see scheme), benzofurans, tetrahydrofurans, pyrrolidines, pyrans, piperidines, and various polycyclic compounds. The reactions proceed under mild conditions that circumvent the use of reactive leaving groups like halides.
The eco-friendly and highly diastereoselective synthesis of substituted cis-2,6-piperidines and cis-2,6-tetrahydropyrans is described. The key step of this method is the iron-catalyzed thermodynamic equilibration of 2-alkenyl 6-substituted piperidines and 2-alkenyl 6-substituted tetrahydropyrans allowing the isolation of enriched mixtures of the most stable cis-isomers.
Doherty, Annette M.; Ley, Steven V.; Lygo, Barry, Journal of the Chemical Society. Perkin transactions I, 1984, p. 1371 - 1378
作者:Doherty, Annette M.、Ley, Steven V.、Lygo, Barry、Williams, David J.
DOI:——
日期:——
YADAV, J. S.;STEENIVASA, RAO E.;RAO, C. S.;CHOUDARY, B. M., J. MOL. CATAL., 49,(1989) N, C. L61-L63
作者:YADAV, J. S.、STEENIVASA, RAO E.、RAO, C. S.、CHOUDARY, B. M.