Switchable Reactions of Cyclopropanes with Enol Silyl Ethers. Controllable Synthesis of Cyclopentanes and 1,6-Dicarbonyl Compounds
作者:Jian-Ping Qu、Chao Deng、Jian Zhou、Xiu-Li Sun、Yong Tang
DOI:10.1021/jo901340v
日期:2009.10.16
Cu(SbF6)2-catalyzed reaction of 2-substituted cyclopropane-1,1-dicarboxylates 1 with enol silyl ethers 2 can be readily controlled: the reaction undergoes a cycloaddition to provide substituted cyclopentane derivatives 3 in excellent yields with high diastereoselectivities in the presence of complex 8/Cu(II); however, the same substrates afford acyclic 1,6-dicarbonyl products 4 via a cycloaddition−ring-opening
Cu(SbF 6)2催化2-取代的环丙烷-1,1-二羧酸酯1与烯醇甲硅烷基醚2的反应很容易控制:该反应进行环加成反应,以优异的收率提供取代的环戊烷衍生物3,并具有很高的非对映选择性。络合物8 / Cu(II)的存在;然而,在没有配体8的情况下,相同的底物可通过环加成-开环反应以高达92%的产率提供无环1,6-二羰基产物4。对照实验和1均研究了配体可转换反应的机理。1 H NMR研究。还检查了基板范围和可调变换的局限性。