Catalytic Asymmetric Halohydroxylation of α,β‐Unsaturated Ketones with Water as the Nucleophile

The catalytic asymmetric halohydroxylation of α,β‐unsaturated ketones with water as the nucleophile has been realized by applying a chiral N , N′ ‐dioxide/Fe(OTf) 2 complex as the catalyst. Bromo‐, chloro‐ and iodo‐hydroxylations were all suitable in this catalytic system. A variety of α‐halo‐β‐hydroxy ketones were obtained in often good yields with generally high dr and ee values. Besides, a Michael/α‐halogenation process was considered more possible and a possible transition state model was proposed to explain the origin of stereoselectivity.