Scope and Mechanistic Investigations on the Solvent-Controlled Regio- and Stereoselective Formation of Enol Esters from the Ruthenium-Catalyzed Coupling Reaction of Terminal Alkynes and Carboxylic Acids.

ABSTRACT: The ruthenium-hydride complex (PCy(3))(2)(CO)RuHCl was found to be a highly effective catalyst for the alkyne-to-carboxylic acid coupling reaction to give synthetically useful enol ester products. Strong solvent effect was observed for the ruthenium catalyst in modulating the activity and selectivity; the coupling reaction in CH(2)Cl(2) led to the regioselective formation of gem-enol ester products, while the stereoselective formation of (Z)-enol esters was obtained in THF. The coupling reaction was found to be strongly inhibited by PCy(3). The coupling reaction of both PhCO(2)H/PhC identical withCD and PhCO(2)D/PhC identical withCH led to the extensive deuterium incorporation on the vinyl positions of the enol ester products. An opposite Hammett value was observed when the correlation of

SUBMITTER: Yi CS 

PROVIDER: S-EPMC2782529 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature