New method for the selective reduction of amides

Abstract

A new procedure was developed for the reduction of tertiary aliphatic, olefinic, and aromatic amides to aldehydes. Reaction of the amides (1), (5), (7), (9), (11), (13), (15), and (17) with ethyl or methyl trifluoromethanesulphonate in CH₂Cl₂ at room temperature and then with L-Selectride at –78 °C gave the corresponding aldehydes (2), (6), (8), (10), (12), (14), (16), and (18), respectively. A second functional group, including CO₂R, CC, CH(OCH₂CH₂O), and CN, in these amides was found to be inert under the conditions employed. These selective reductions gave the desired aldehydes in 50–73% isolated yields and in >95% yields based on converted amides.