Acyclic stereocontrol through the thio-Claisen rearrangement of precursors bearing a chiral centre adjacent to carbon 1
作者:Stéphane Désert、Patrick Metzner、Mohamed Ramdani
DOI:10.1016/s0040-4020(01)88336-8
日期:1992.11
The Claisen rearrangement of precursors bearing a stereogenic centre adjacent to carbon 1 of the pericyclic nucleus has been investigated in the sulfur series. Dithioesters having a methyl and various alkyl or alkenyls groups on the β-carbon were deprotonated by LDA. The resulting enethiolates were allylated on sulfur to give S-allyl ketenedithioacetals. The thio-Claisen transposition of the latter
在硫系列中,已经研究了具有与周环核碳1相邻的立体中心的前体的克莱森重排。通过LDA使在β-碳上具有甲基和各种烷基或烯基的二硫代酯去质子化。将得到的烯硫醇盐在硫上烯丙基化,得到S-烯丙基酮二硫缩醛。后一种化合物的硫代-克莱森转位在室温或101℃下均可实现,以得到良好的烯丙基化二硫代酯收率。已经观察到非对映异构体选择性高达95:5。这些结果已通过空间效应进行了解释,并与烯丙基应变值相关。