Convenient enol equivalents for catalytic aldol-transfer reactions

Solid crystalline and stable 1,1-diphenyl-1-hydroxy-3-butanone was shown to serve as an excellent precursor of the Al-enolate of acetone generated in situ for Al-BINOL catalyzed aldol-transfer reactions of aldehydes. The best yields were obtained with electron rich aromatic aldehydes and 2-pyridine carbaldehyde of which the latter gave 1-hydroxy-1-(2-pyridyl)-3-butanone in 79% yield.