Photoenolization with α-Chloro Substituents

Article abstract of DOI:10.1021/jo00350a036

Irradiation of a methanol solution of 2,5-dimethyl-α-chloropropiophenone (1a) produces 2,6-dimethyl-1-indanone (2a), 2-(methoxymethyl)-5-methylpropiophenone (3a), 2,5-dimethylpropiophenone (4a), and methyl 2-(2,5-dimethylphenyl)propionate (5a).It is proposed that the first two products arise from hydrogen abstraction followed by chlorine loss, the latter two from initial loss of chlorine.Making the chlorine-bearing carbon primary suppresses the formation of the latter two products, while maintaining the carbonyl nearly planar with the ring suppresses all product formation.Other examples are presented.