Partial Reduction of Tertiary Amides to Aldehydes Using a New Reducing Agent, Lithium Diisobutyl-iso-propoxyaluminum Hydride (LDBIPA)

摘要

Partial reduction of carboxylic acid derivatives to aldehydes with efficient reducing agents is one of the important techniques in organic synthesis; hence, large numbers of useful reducing agents for this purpose have been reported over a long time. Recently, we have found and reported that a new class of reducing agents including lithium diisobutylpiperidinohydroalumi-nate (LDBPA), lithium diisobutyl-t-butoxyaluminum hydride (LDBBA) and sodium diisobutyl-t-butoxyaluminum hydride (SDBBA) showed effective partial reducing characteristics for various esters and acid chlorides. However, these reducing a-gents were not very effective for tertiary amides and nitriles, that are usually easier targets than esters for partial reduction. Therefore, we decided to develop new and effective reducing agents that can achieve partial reduction of tertiary amides with excellent yields in the course of our development work in the area of partial reduction of carboxylic acid derivatives.