The mimic of type II aldolases chemistry: asymmetric synthesis of beta-hydroxy ketones by direct aldol reaction.

An efficient direct aldol reaction has been developed for the synthesis of chiral beta-hydroxy ketone using a combination of C(1)-symmetric chiral prolinamides based on o-phenylenediamine and zinc triflate as catalyst. The reaction was convenient to carry out in aqueous media with up to 98% chemical yields and up to 94% ee values. The current strategy can be regarded as the analogue of aldolase type II, which suggests a new pathway for the designing of new organocatalysts.