期刊
CHEMISTRY-AN ASIAN JOURNAL
卷 6, 期 8, 页码 2100-2105出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/asia.201100190
关键词
alkenes; allenoates; annulation; phosphine catalysis; regioselectivity
资金
- U.S. National Institutes of Health [R01M071779, P41M081282]
From our investigations on phosphine-catalyzed [4+2] annulations between alpha-alkyl allenoates and activated olefins for the synthesis of cyclohexenes, we discovered a hexamethylphosphorous triamide (HMPT)-catalyzed [4+2] reaction between alpha-alkyl allenoates 1 and arylidene malonates or arylidene cyanoacetates 2 that provides highly functionalized cyclohexenes 3 and 4 in synthetically useful yields (30-89%), with moderate to exclusive regioselectivity, and reasonable diastereoselectivity. Interestingly, the [4+2] annulations between the alpha-alkyl allenoates 1 and the olefins 2 manifested a polarity inversion of the 1,4-dipole synthon 1, depending on the structure of the olefin, thus providing cyclohexenes 3 exclusively when using arylidene cyanoacetates. The polarity inversion of alpha-alkyl allenoates from a 1,4-dipole A to B under phosphine catalysis can be explained by an equilibrium between the phosphonium dienolate C and the phosphorous ylide D.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据