Efficient Aldol Addition of Simple Thioesters

Significance

The authors found a very practical method for the preparation of aldols starting from thioesters and some classes of aldehydes. The yields are uniformly good for benzaldehydes and hindered aliphatic aldehydes. Thiophenyl acetate is a commercially available reagent and other reaction participants are inexpensive. The process is simple, does not require special precautions and is very fast at room temperature. Thioesters other than acetyl derivatives can also be used, but no diastereoselectivity is observed in the formation of the corresponding aldol products. An additional advantage of the thioester aldols is the increased reactivity of the acyl group, compared to usual esters, toward nucleophilic attacks in processes like reduction, hydrolysis or amidation.