Synthesis of Enantioenriched Bromohydrins via Divergent Reactions of Racemic Intermediates from Anchimeric Oxygen Borrowing

We report a chiral
phosphoric acid catalyzed bromocyclization/regiodivergent
reaction of racemic intermediates sequence, which is enabled by anchimeric
oxygen borrowing. Different types of alkenes are applicable, and both
enantiomers of the bromohydrin products were obtained in generally
excellent yields and enantioselectivities. In addition, an example
of enantioconvergent synthesis from the two isomeric products is presented.