Synthesis of vinylcyclopropanes via palladium-catalyzed coupling of cyclopropylzinc halides with vinyl iodides. Total syntheses of (±) -prezizanol and (±)-prezizaene
作者:Edward Piers、Michel Jean、Peter S. Marrs
DOI:10.1016/s0040-4039(00)95593-x
日期:——
Palladium(O)-catalyzedcoupling of cyclopropylzinc halides, readily prepared from the corresponding cyclopropyl (tri--butyl)stannanes, with vinyl iodides provides good yields of functionalized vinylcyclopropanes. The coupling reaction is used as a key step in total syntheses of the sesquiterpenoids (±)-prezizanol and (±)-prezizaene.
Cyclopentenone formation via hydrogen activation in the reactions of chromium carbene complexes with alkynes
作者:Cynthia A. Challener、William D. Wulff、Benjamin A. Anderson、Steve Chamberlin、Katherine L. Faron、Oak K. Kim、Christopher K. Murray、Yao Chang Xu、Dominic C. Yang、Stephen D. Darling
DOI:10.1021/ja00057a020
日期:1993.2
alkyl chromium carbene complexes with alkynes have been found to give cyclopentenones. Mechanisms are proposed to account for the formation of these products that involve metal hydride intermediates. As has been previously reported for tungsten, molybdenum alkyl complexes have been found to give 1,3-dienes rather than cyclopentenones. The difference between chromium and molybdenum and tungsten may be