Asymmetric reduction of prochiral aromatic ketones by Borane-Amine complexes in the presence of a chiral amine-BF < inf > 3 < /inf > catalyst

Abstract

The (-)-N-α-Methylbenzyl-3,5-dihydrodinaphthazepine-BH3 complex reduces aromatic ketones to alcohols with 11-57% enantiomeric excess (e.e.) in the presence of BF3·OEt2, the (-)-N-α-methylbenzyl-3,5 dihydrodinaphthazepine-BF3 complex catalyses asymmetric reduction of acetophenone by N,N′-diethylaniline- BH3 to give α-phenylethyl alcohol in 51% e.e.