Organo- and Metal Catalysis Complement Each Other

Significance

The authors report the efficient enantioselective α,α-dihalogenation of carbonyl compounds. Monochlorinated aldehydes such as 1 were successfully converted into the α,α-chlorofluoro aldehydes involving a fluorine source and the Hayashi-Jørgensen chiral catalyst. Ketones such as example 2 were transformed into the di­halogenated product by assistance of metal catalysis. A fluorinated silyl enolate equivalent was selectively chlorinated in the presence of a transition-metal salt and a chiral chlorine source. The versatility of both types of products was shown by different subsequent transformations, such as Grignard addition and oxidation or nucleophilic substitution, respectively.