Asymmetric Morita-Baylis-Hillman reactions catalyzed by chiral Brønsted acids
Nolan T McDougal1, Scott E Schaus
1Department of Chemistry, Metcalf Center for Science and Engineering, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA.
Abstract:
Chiral BINOL-derived Brønsted acids catalyze the enantioselective asymmetric Morita-Baylis-Hillman (MBH) reaction of cyclohexenone with aldehydes. The asymmetric MBH reaction requires 2-20 mol % of the chiral Brønsted acid 2e or 2f and triethylphosphine as the nucleophilic promoter. The reaction products are obtained in good yields (39-88%) and high enantioselectivities (67-96% ee). The Brønsted-acid-catalyzed reaction is the first example of a highly enantioselective asymmetric MBH reaction of cyclohexenone with aldehydes.
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