Organic syntheses by means of noble metal compounds. XXXV. Novel decarbonylation reactions of aldehydes and acyl halides using rhodium complexes

Abstract

It was found that aldehydes are decarbonylated by the reaction with chlorotris(triphenylphosphine)-rhodium under mild conditions. Acyl halides are also decarbonylated to give olefins. Five-coordinate acylrhodium complexes were isolated as an intermediate of the reaction by oxidative addition of acyl halides to the complex. Several transformations of the acyl-rhodium complexes were carried out. Chlorocarbonylbis(triphenylphosphine) rhodium is an efficient catalyst of the decarbonylation of acyl halides and aldehydes; aromatic acid halides can be decarbonylated smoothly to give aromatic halides in the presence of a catalytic amount of this complex. The carbonylation of reactive alkyl halides to give acyl halides also is catalyzed by the complex. The mechanism of the decarbonylation and carbonylation reactions is discussed. © 1968, American Chemical Society. All rights reserved.