Chemoselective Reduction of Phenyl Ketones with Amino Alcohol–Borane Complexes

Abstract

Abstract A new reducing agent was prepared from borane and amino alcohols. The reagent is very effective for chemoselective reduction of ketones in the presence of esters, oxime ethers, tertiary amides, nitriles, halides, and acyl chlorides. The polymeric reagent prepared from borane and polymer-supported amino alcohol was also prepared easily. Aldehydes are highly selectively reduced to primary alcohols in the presence of ketone with the polymeric reagent. Simple filtration separated cleanly the unchanged ketone from the polymeric reagent which gave, after hydrolysis, only primary alcohol as the product. The polymeric reagent was regenerated by treatment with borane and could be reused.