Investigation of the Chemo- and Stereoselectivity of the Ketene-Claisen Rearrangement
作者:Beat Ernst、Reinhold Oehrlein、Daniel Bellu?、Jozef Gonda、Rainer Jeschke、Udo Nubbemeyer
DOI:10.1002/hlca.19970800321
日期:1997.5.12
A novel type of ketene-Claisen rearrangement in which the precursor of the rearrangement is generated in situ by reaction of optically active allyl thioethers with dichloroketene is described. A characteristic feature of this rearrangement is the excellent chemoselectivity in favor of allyl thioethers vs. allyl ethers, i.e., exclusive chirality transfer of the allylic sulfur moiety is observed with
描述了一种新型的烯酮-克莱森重排,其中通过光学活性的烯丙基硫醚与二氯烯酮的反应原位产生重排的前体。这种重排的特征是相对于烯丙基醚而言,有利于烯丙基硫醚的出色的化学选择性,即在12、13和25--27处观察到烯丙基硫部分的手性转移。环状光学活性烯丙基硫醚(+)-(R)-4和(-)-(S)-4和开链烯丙基硫醚11--13重排,原位生成的二氯乙烯酮分别形成旋光的硫酯(-)-(S)-28,(+)-(R)-28和31-33。在循环情况(+)-(R)-4和(-)-(S)-4中,手性转移> 99%,在开链情况11--13中观察到96--98%。此外,二氯乙烯烯-克莱森重排的特征在于高的不对称1,2-诱导。手性烯丙基硫化物25--27得到旋光的硫酯36--38 通过NMR位移实验测得的1,2-诱导> 99%。