Reaction ofα- Halo Ketones with Nucleophiles

Article abstract of DOI:10.1021/ja00294a050

p-Nitro- or p-cyanophenacyl chloride or the 1,1-dimethyl derivatives react with the anion of 2-nitropropane to form the C-alkilation product by a radical chain mechanism (S_RN1).With the 1,1-dimethyl derivatives, the free radical substitution is photostimulated and occurs in competition with ionic reactions leading to the oxiranes 5 and hydroxy ketones 6.When K⁺ is used as the counterion, the S_RN1 process is favored by complexation with 18-crown-6. p-Nitro-1,1-dimethylphenacyl chloride gives substitution products with diethyl malonate or diethyl mthylmalonate anions via the S_RN1 process, but with PhS^- or p-MeC6H4SO2^-, substitution occurs by competing ionic and radical processes.Propylacetylenide anion reacts to form the oxirane 13a while diethyl phosphite or thiophosphite anions yield the enol phosphate 14a or thiophosphate 14b. 1,1-Dimethylphenacyl chloride reacts by nonradical processes to give the oxirane with acetylenide anions, the substitution products with PhS^- or p-MeC6H4SO2^- and a mixture of the enol phosphate, and oxirane 16 with diethyl phosphite anion.With Me2C==NO2^-K⁺, mainly the oxirane is formed in Me2SO but mainly substitution via the S_RN1 chain is observed in HMPA.