mixtures of isomers and substantial polymerization. The reaction took place under exceptionally mild reaction conditions and very low catalyst loading (0.5 mol %). DFT calculations disclose the mechanistic features of the isomerization and account for the high selectivity displayed by the B(C6 F5 )3 catalyst. The synthetic applicability of the newreaction is demonstrated by the preparation of γ-chiral
Cross-coupling reaction of organosilicon nucleophiles
申请人:——
公开号:US20020183516A1
公开(公告)日:2002-12-05
Improved methods for generating a —C—C— bond by cross-coupling of a transferable group with an acceptor group. The transferable group is a substituent of an organosilicon nucleophile and the acceptor group is provided as an organic electrophile. The reaction is catalyzed by a Group 10 transition metal complex (e.g., Ni, Pt or Pd), particularly by a palladium complex. Certain methods of this invention use improved organosilicon nucleophiles which are readily prepared, can give high product yields and exhibit high stereo selectivity. Methods of this invention employ activating ions such as halides, hydroxide, hydride and silyloxides. In specific embodiments, organosilicon nucleophilic reagents of this invention include siloxanes, particularly cyclic siloxanes. The combination of the cross-coupling reactions of this invention with ring-closing metathesis, hydrosilylation and intramolecular hydrosilylation reactions provide useful synthetic strategies that have wide application.
Unconventional isomerization of allylic alcohols to allylcarbinols mediated by lanthanide catalysts
作者:SungYong Seo、Xianghua Yu、Tobin J. Marks
DOI:10.1016/j.tetlet.2013.01.111
日期:2013.4
We report here the catalytic isomerization of aryl-substituted allylic alcohols mediated by lanthanide alkoxide complexes. The conversion yields allylcarbinols as the products of the olefin isomerization process, but with different olefinic positions than those afforded by typical transition metal catalysts. The average isolated product yields in these reactions are 65–81%. The catalytic cycle and