作者:Tobias Wagner、Jens Lange、Dirk Grote、Wolfram Sander、Ernst Schaumann、Gunadi Adiwidjaja、Arnold Adam、Jürgen Kopf
DOI:10.1002/ejoc.200900482
日期:2009.10
ethylsilanes 12 by base-induced α-elimination. This is confirmed by [2+1] cycloadditions with alkenes to give the cyclopropanes 4a–d and 14. Product 4a is identical with the product obtained from carbanion 1c, phenyloxirane, and styrene, for which a carbene intermediate 5a had been invoked. On heating in the presence of copper triflate, cyclopropane 4a undergoes ring enlargement to the thiochroman
标题卡宾 5 可以通过铜催化催化从重氮化合物 9 或通过碱诱导的α-消除从氯(有机硫基)甲基硅烷 12 生成。这通过与烯烃进行 [2+1] 环加成得到环丙烷 4a-d 和 14 得到证实。产物 4a 与从碳负离子 1c、苯基环氧乙烷和苯乙烯获得的产物相同,为此已调用卡宾中间体 5a。在三氟甲磺酸铜存在下加热时,环丙烷 4a 环扩大为硫色满 11。对于(Z)-或(E)-烯烃 20,卡宾 5a 形成立体有择的环丙烷,尽管马来酸盐不是合适的指示剂立体有择环加成。DFT 计算 (B3LYP/cc-pVTZ) 证实了建议的单线态 5。环丙烷4a和23的结构,