Thermal Decomposition of Pentacarbonyl(1-acyloxyalkylidene)chromium(0) Complexes: Formation of Z-Enol Esters
摘要:
Pentacarbonyl(1-acyloxyalkylidene)chromium(0) complexes, formed in situ by reaction of the corresponding tetramethylammonium pentacarbonyl(1-oxoalkyl)chromate(1-) salts with carboxylic acid halides, affords enol esters in moderate to good yields. In all cases examined, the Z-enol ester was obtained as the major or exclusive isomer. Addition of I equiv of pyridine to the reaction mixture substantially improved the Z/E ratio and, in most cases, increased the chemical yield.