Enantioselective addition of phenylacetylene to aldehydes catalyzed by polymer-supported titanium(IV) complexes of β-hydroxy amides

Abstract

A series of polymer-supported chiral β-hydroxy amides and C 2-symmetric β-hydroxy amides have been synthesized and successfully used for the enantioselective addition of phenylacetylene to aldehydes. High yields (up to 93%) and enantioselectivities (up to 92% ee) were achieved by using polymer-supported chiral bhydroxy amide 4b. The resin 4b is reused four times, giving the product with enantioselectivity 80% ee. Fortunately, it is found that this heterogonous system is suitable not only for aromatic aldehydes but also aliphatic aldehyde. © 2009 Wiley-Liss, Inc.