Stereoselectivity of the Petasis reaction with various chiral amines and styrenylboronic acids

Churches, Quentin I.; Stewart, Helen E.; Cohen, Scott B.; Shröder, Adam; Turner, Peter; Hutton, Craig A.

doi:10.1351/pac200880040687

Pure Appl. Chem., 2008, Vol. 80, No. 4, pp. 687-694

http://dx.doi.org/10.1351/pac200880040687

Stereoselectivity of the Petasis reaction with various chiral amines and styrenylboronic acids

Quentin I. Churches¹, Helen E. Stewart², Scott B. Cohen², Adam Shröder¹, Peter Turner² and Craig A. Hutton¹

¹ School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, VIC 3010, Australia
² School of Chemistry, The University of Sydney, NSW 2006, Australia

Abstract: Several chiral amines were investigated for the stereoselective preparation of homophenylalanine derivatives using the Petasis reaction. Chiral secondary amines such as N,α-dimethylbenzylamine and N-benzylphenylglycinol gave the best results in terms of both yield and diastereoselectivity. The use of N-benzylphenylglycinol leads directly to 3-alkenyl-4-benzyl-5-phenyloxazin-2-one products. Intriguing variation was observed in the stereoselectivity of reactions employing para-substituted styrenylboronic acid substrates, where presumably only electronic factors are involved.