Controlled reduction of tertiary amides to the corresponding aldehydes or amines using dialkylboranes

Article abstract of DOI:10.1016/S0040-4039(97)00179-2

Several tertiary amides were reduced using one or two equivalents of various dialkylboranes, such as 9-borabicyclo[3.3.1] nonane (9-BBN), dicyclohexylborane (Chx₂BH), or disiamylborane (Sia₂BH). The reduction of tertiary amides having alkyl substituents of varying steric requirement at the nitrogen atom, required two equivalents of 9-BBN for complete reduction and gave the corresponding tertiary amines. However, sterically more hindered dialkylboranes such as Chx₂BH and Sia₂BH, reacted in 1:1 stoichiometry with tertiary amides and partially reduced them to the corresponding aldehydes.