A Chemoselective Reduction of Alkynes to (<i>E</i>)-Alkenes
作者:Barry M. Trost、Zachary T. Ball、Thomas Jöge
DOI:10.1021/ja026457l
日期:2002.7.1
The trans reduction of all types of alkynes to give (E)-olefins is achieved through a two-stage trans hydrosilylation and protodesilylation. Reaction of an alkyne and a silane with the ruthenium catalyst [Cp*Ru(MeCN)3]PF6 results in clean hydrosilylation to give only the (Z)-trans addition product at ambient temperature with catalyst loadings of 1-5 mol %. The crude vinylsilane products are then protodesilylated by the action of cuprous iodide and TBAF at rt-35 degrees C. The reaction is compatible with many sensitive functional groups and provides a general trans-alkyne reduction not possible by other means.
Fe(III)/Cu(II) mediated 5- and 6-exo oxidative ring expansion/cyclisation of cyclopropyl ethers: studies towards dictyol C and α-eudesmol
作者:Kevin I Booker-Milburn、Brian Cox、Mick Grady、Frank Halley、Shaun Marrison
DOI:10.1016/s0040-4039(00)00648-1
日期:2000.6
The outcome of oxidative ring expansion/cyclisation of cyclopropanes with a mixed Fe(III)/Cu(II) system was found to be dependent on the mode of cyclisation. When 6-exo cyclisation was attempted unusual products resulting from oxidation of ring opened primary radicals were obtained. (C) 2000 Elsevier Science Ltd. All rights reserved.