Ruthenium-Catalyzed One-Step Transformation of Propargylic Alcohols into Alkylidene Cyclobutenes: X-ray Characterization of an Ru(η3-cyclobutenyl) Intermediate
作者:Jacques Le Paih、Sylvie Dérien、Christian Bruneau、Bernard Demerseman、Loïc Toupet、Pierre H. Dixneuf
The precatalyst [Cp*RuCl(cod)] promotes the head-to-head cyclodimerization of propargylic alcohols and the formation of novel alkylidene cyclobutenes (see scheme; Cp*=C5 Me5 , cod=1,5-cyclooctadiene) by addition of carboxylic acid to the Ru(η4 -cyclobutadiene) intermediate and dehydration.
Ruthenium-Catalyzed Synthesis of Alkylidenecyclobutenes via Head-to-Head Dimerization of Propargylic Alcohols and Cyclobutadiene-Ruthenium Intermediates
作者:Jacques Le Paih、Sylvie Dérien、Bernard Demerseman、Christian Bruneau、Pierre H. Dixneuf、Loïc Toupet、Georg Dazinger、Karl Kirchner
DOI:10.1002/chem.200400899
日期:2005.2.4
derivatives, in the presence of the precatalyst [RuCl(cod)(C5Me5)] leads selectively to a variety of alkylidenecyclobutenes through head-to-headdimerization of propargylic alcohol. The first step is the formation of a cyclobutadiene-ruthenium intermediate resulting from the head-to-head coupling of two molecules of propargylic alcohol. On protonation with strong acids (HPF6, HBF4) dehydration of the cyclobutadiene