Alkylation thiolate-bridged diruthenium

The catalytic propargylic alkylation was investigated in the presence of thiolate-bridged diruthenium complexes as catalysts generated in situ from reactions of [Cp RuCl(p2-Cl)]2 with optically active thiols prepared from the corresponding optically active alcohols [27]. Typical results for the reaction of 1-phenyl-2-propyn-l-ol with acetone in the presence of a variety of catalysts are shovm in Scheme 7.19. 

The thiolate-bridged diruthenium complex 101 can promote a cycloaddition reaction between propargylic alcohols and 1,3-dicarbonyl compounds to provide 3-acyM//-pyrans in excellent yield (Scheme 33). The reaction proceeds via formation and alkylation of the allenylidene complex 102 to form the vinylidene intermediate 103, which upon cyclization furnishes 4//-pyrans (Scheme 33) <2004JOC3408>. 

The enantioselective propargylic alkylation of propargyUc alcohols with aldehydes [188] or p-ketoesters [189] has recently been accomplished by cooperative catalytic reactitMis using a thiolate-bridged diruthenium complex and a chiral... 

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