Azetidine-derived bifunctional organocatalysts for Michael reactions

作者：Menguy Laurence; Couty Francois^*

来源：Tetrahedron: Asymmetry , 2010, 21(19): 2385-2389.

DOI：10.1016/j.tetasy.2010.08.003

2-Cyano azetidines, easily accessible from beta-amino alcohols, are precursors of stereodefined homochiral azetidinic or pyrrolidinic 1,2-diamines. A small library of these original diamines was screened as precatalysts for the enantioselective addition of 1,3-dicarbonyl compounds onto beta-nitro styrenes. An azetidinic diamine derived from (-)-ephedrine and derivatized as a thiourea was found to catalyze the conjugate addition of acetylacetone with good levels of enantioselectivities (up to 84% ee). Interestingly, the absolute configuration of the Michael adduct depends on the nature of the 1,3 dicarbonyl nucleophile (diethyl malonate or acetylacetone), which is indicative of a different mechanism involved in the reaction of these two nucleophiles.

• 出版日期2010-10-7