Boron-catalyzed direct aldol reactions of pyruvic acids.

Interactions between pyruvic acids and diphenylborinic acid form the basis of an efficient, direct, boron-catalyzed aldol reaction that takes place in water at room temperature with low catalyst loadings. Both boronic and borinic acids function as catalysts, with the latter demonstrating particularly high activity. A wide range of aldehydes, including enolizable species, may be employed, delivering useful isotetronic acid derivatives in high yields.