Oxidative Acylation of Alcohols in the Presence of Amines

Significance

A highly chemoselective acylation of various alcohols in the presence of amines by oxidative esterification using a readily available and cheap organic oxidant is reported. Excellent chemoselectivities were obtained for ortho-, meta-, and para-substituted benzaldehyde derivatives and for heteroaromatic aldehydes. The activated aliphatic α-benzoyloxyacetaldehyde was also transformed to the corresponding benzyl ester with high chemoselectivity. It is suggested that two carbenes act cooperatively in the oxidative acylation which is supported by quantum mechanical calculations. The authors propose that the chemoselectivity results from preferable activation of the alcohol by H-bonding.