Angewandte Chemie International Edition

Steven T. Scroggins, Yonggui Chi, and Jean M. J. Fréchet*

The concept of using polarity differences to direct reactions is demonstrated in a novel one-pot cascade sequence of condensation followed by conjugate addition. The two-step reaction incorporates nitromethane and two aliphatic aldehydes with similar chemical reactivities. Under typical homogeneous conditions either aldehyde can be incorporated at each step of the reaction, and a statistical mixture is formed of four equally favored products. In contrast, the use of a biphasic reaction medium with two different organic catalysts results in the selective incorporation of both aldehydes with a strong preference for a major "cross" product.