Highly chemoselective reduction of carbonyl groups in the presence of aldehydes.

The exquisite ability of diethylaluminum benzenethiolate to efficiently discriminate between aldehydes and other carbonyl functions enables the chemoselective in situ reduction of ketones and methyl esters in the presence of aldehydes. This potent strategy avoids the usual drawbacks of traditional protecting group methodologies and could be extended to various other transformations.