Exploring new reactive species for cyclopropanation
作者:Zhiqiang Yang、Jon C. Lorenz、Yian Shi
DOI:10.1016/s0040-4039(98)01954-6
日期:1998.11
An organozinc species RXZnCH2I generated by reacting Zn(CH2I)2 with RXH was found to be an efficient reagent for the cyclopropanation of olefins at room temperature. A 50.7% ee was obtained for the cyclopropanation of trans-β-methylstyrene when a chiral alcohol was used.
Dialkylation of gem-dibromocyclopropanes with trialkylmanganate and manganese(II) chloride-catalyzed reaction with alkylmagnesium bromide
作者:Rie Inoue、Hiroshi Shinokubo、Koichiro Oshima
DOI:10.1016/0040-4039(96)01082-9
日期:1996.7
gem-dibromocyclopropanes with trialkylmanganate, derived from manganese(II) chloride and three equivalents of Grignard reagent or alkyllithium, followed by an addition of electrophiles provided dialkylated cyclopropanes in good yields. It was found the reaction with alkylmagnesium halide proceeded in the presence of a catalytic amount of manganese(II) chloride.
A Novel Class of Tunable Zinc Reagents (RXZnCH<sub>2</sub>Y) for Efficient Cyclopropanation of Olefins
作者:Jon C. Lorenz、Jiang Long、Zhiqiang Yang、Song Xue、Yinong Xie、Yian Shi
DOI:10.1021/jo030312v
日期:2004.1.1
A class of zincreagents (RXZnCH2Y) generated with an appropriate organozinc is very effective for the cyclopropanation of olefins. The reactivity and selectivity of these reagents can be regulated by tuning the electronic and steric nature of the RX group on Zn. A reasonable level of enantioselectivity was obtained for the cyclopropanation of unfunctionalized olefins when a chiral (iodomethyl)zinc