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

The catalytic asymmetric halohydroxylation of alpha,beta-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 alpha-halo-beta-hydroxy ketones were obtained in often good yields with generally high dr and ee values. Besides, a Michael/alpha-halogenation process was considered more possible and a possible transition state model was proposed to explain the origin of stereoselectivity.