A DFT study of the enantioselective reduction of prochiral ketones promoted by pinene-derived amino alcohols

Abstract

Recently, a pinene-derived amino alcohol [(1 R,2 R,3 S,5 R)-3-amino-2,6,6-trimethylbicyclo[3.1.1]heptan-2-ol] has been experimentally employed as an effective chiral catalytic precursor in the borane-mediated asymmetric reduction of prochiral ketones to produce the corresponding secondary alcohols, which provides the products in 96% ee. In this paper, we suggest a mechanism for this reduction process and then theoretically investigate it in detail by density functional theory. Fully geometry-optimized reactants, products, transition structures, and intermediates were obtained at the B3LYP/6-31G (d,p) level, and the results reveal that this reaction has five steps. Further calculations show that the solvent effect of THF has no great influence on the enantioselectivity of this reduction.