Dehalogenation of a-haloacyl halides

The dehalogenation of a-haloacyl halides with zinc occurs readily, particularly for the formation of aromatic ketoketenes like methylphenyl-ketene (90%), diphenylketene (95%),and di-p-xenylketene (60%)/ ... 

Consequently, haloketenes can be readily generated in situ by two most widely used methods (a) the triethylamine dehydrohalogenation of an acyl halide (Eq. (3))50) (b) the dehalogenation of an a-haloacyl halide with activated zin (Eq. (4))51). Since the halogen substituents on the cyclobutanone can be reductively removed by usual procedures, the synthesis of a halocyclobutanone constitutes a formal preparation of the cyclobutanone, the synthetic utility of which is convincingly demonstrated by the following examples. 

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