Asymmetric, Regioselective Bromohydroxylation of 2-Aryl-2-propen-1-ols Catalyzed by Quinine-Derived Catalysts

The asymmetric bromohydroxylation of 2-aryl-2-propen-1-ols catalyzed by quinine-derived bifunctional catalyst has been developed. The regioselectivity was controlled by employing a boronate ester as tether which was formed in situ and enantioselectivity was introduced by taking advantage of a quinine-derived bifunctional catalyst which activated the boronate ester and N-bromosuccinimide (NBS) at the same time. Chiral bromohydrin, which is a useful feedstock in organic synthesis, was produced in moderate to excellent enantioselectivity in a two-step reaction sequence.