Journal of the American Chemical Society 2009-11-25

Asymmetric histidine-catalyzed cross-aldol reactions of enolizable aldehydes: access to defined configured quaternary stereogenic centers.

Morris Markert, Ulf Scheffler, Rainer Mahrwald

Index: J. Am. Chem. Soc. 131(46) , 16642-3, (2009)

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Abstract

A histidine-catalyzed asymmetric direct cross-aldol reaction of enolizable aldehydes is described. In contrast to proline, histidine is able to clearly differentiate the reactivity of various aldehydes. In addition, this approach provides access to syn-configured beta-hydroxyaldehydes. Thus, by application of this new methodology, defined-configuration quaternary stereocenters can be constructed with ease. The utility of this method is demonstrated in several total syntheses of branched-chain carbohydrates.