B(C6F5)3-Catalyzed Deoxygenative Reduction of Amides to Amines with Ammonia Borane

The first B(C6F5)(3)-catalyzed deoxygenative reduction of amides into the corresponding amines with readily accessible and stable ammonia borane (AB) as a reducing agent under mild reaction conditions is reported. This metal-free protocol provides facile access to a wide range of structurally diverse amine products in good to excellent yields, and various functional groups including those that are reduction-sensitive were well tolerated. This new method is also applicable to chiral amide substrates without erosion of the enantiomeric purity. The role of BF3OEt2 co-catalyst in this reaction is to activate the amide carbonyl group via the insitu formation of an amide-boron adduct.