Studies on Conjugated Nitriles. IV. Reaction of Ethyl Cyanoformate with Organomagnesium, -zinc, and-cadmium Reagents, and Phosphonium Ylide

Abstract

The reaction of ethyl cyanoformate (1a) with phenylcadmium bromide (3a) gave ethyl benzoate (4), ethyl 2-phenyl-2-oxoacetate (5a), and 2-ethoxycarbonyl-2, 4-diphenyl-3-imidazolin-5-one (6). In the presence of zinc chloride, the addition of 3a to the cyano group of 1a occurred to give only 5a. The similar reaction of 1a with other organocadmium reagents (3b-f) in the presence of zinc chloride gave the corresponding α-ketoesters (5b-f) in moderate yields. The reactions of 1a with other organometallic reagents, e.g. phenylmagnesium (2a), -zinc (8) and-mercuric bromide (9) in the presence or in the absence of zinc chloride were examined. Furthermore, the addition of phosphonium ylide 13a to the cyano group of 1a in the presence of stannic chloride occurred exclusively to give the phosphonium salt 14. The results are discussed in terms of the hard and soft acids and bases (HSAB) principle.