Efficient Carbonyl Addition of Polyfluorochloroethyl, -ethylidene, and -ethenyl Units by Means of 1,1,1-Trichloro-2,2,2-trifluoroethane and Zinc

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Abstract
Thermally stable zinc carbenoid CF3CCl2ZnCl was prepared from 1,1,1-trichloro-2,2,2-trifluoroethane and zinc powder in N,N-dimethylformamide and was allowed to add to carbonyls of aldehydes and α-keto esters in excellent yields to give 1-substituted 2,2-dichloro-3,3,3-trifluoro-1-propanols. Employment of excess zinc induced further reductive β-elimination to afford 1-substituted 2-chloro-3,3,3-trifluoropropenes (3) and 1-substituted 2-chloro-3,3-difluoro-2-propen-1-ols (4). Exclusive formation of 3 was achieved by use of acetic anhydride as the co-reagent, whereas 4 was produced with an aluminium chloride catalyst highly selectively.
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