Asymmetric Morita–Baylis–Hillman reactions catalyzed by chiral Brønsted acids

ORGN 21

Scott E. Schaus1, Nolan T. McDougal2, Whitney L. Trevellini2, Stacy A. Rodgen2, and Laura L. Kliman2. (1) Department of Chemistry and Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, (2) Department of Chemistry, Metcalf Center for Science and Engineering, Boston University, 590 Commonwealth Avenue, Boston, MA 02215
The use of small organic molecules as catalysts to promote asymmetric reactions is a new frontier in reaction methodology development. Asymmetric Brønsted acid-catalysis is a recent addition to this emerging field. 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 1 or 2 and triethylphosphine as the nucleophilic promoter. The reaction products are obtained in good yields and high enantioselectivities. Furthermore, the reaction can be used for the kinetic resolution of racemic α-substituted aldehydes using cyclohexenone and the kinetic resolution of racemic 5-substituted cyclohexenones through the addition to aldehydes. The reactions catalyzed by the chiral binaphthol derivatives represent the first example of a highly enantioselective asymmetric MBH reaction of cyclohexenones with aldehydes.

 

Asymmetric Reactions and Syntheses
8:00 AM-12:00 PM, Sunday, August 22, 2004 Pennsylvania Convention Center -- 201A, Oral

Division of Organic Chemistry

The 228th ACS National Meeting, in Philadelphia, PA, August 22-26, 2004