catalysis. The reaction mechanism has been experimentally investigated and a catalytic cycle involving a C-H/C-H coupling through a new mode of 1,4-palladium migration with concomitant alkene stereoisomerization has been proposed.
The catalytic asymmetric creation of silanes with silicon stereocenters is a long‐sought but underdeveloped topic, and only a handful of examples have been reported. Moreover, the construction of chiral silanes containing (more than) two stereocenters is a more arduous task and remains unexploited. We herein report an unprecedented copper‐catalyzed desymmetrizing protoboration of divinyl‐substituted
Asymmetric silanes: A synthesis of nonracemic alkenylhydrosilanes has been developed based on the desymmetrization of a dihydrosilane through alkenylation with an alkyne using an asymmetric catalyst. The alkenylhydrosilane product can be used as a versatile chiral building block for other functionalized nonracemic silanes through the stereoselective conversion of its hydride and/or alkenyl moiety.
Silicon Tethered Alkenyl Transfer and Type I Ene Reactions
作者:Jeremy Robertson、Garry O'Connor、Caroline L. Ringrose、Donald S. Middleton
DOI:10.1016/s0040-4020(00)00738-9
日期:2000.10
effecting silicon tethered Type I ene cyclisations analogous to our previously reported Type II variant. Some of these substrates were found to undergo overall stereospecific alkenyl transfer via silacyclopentanol intermediates; in a homologous series, alkenyl transfer was accompanied by dehydration to provide 7-silylhepta-2,4-dienes in moderate yield. Formal Type I ene cyclisations were found to be
A variety of functionalized silacyclopentanes were synthesized by highly enantioselective β‐eliminations of silacyclopentene oxides followed by stereospecific transformations. The reaction mechanism of the β‐elimination was elucidated by DFT calculations. An in vitro biological assay with an oxy‐functionalized silacyclopentane showed substantial binding to a serotonin receptor protein.