Role of Diethylaniline in the Reduction of 1,3-Dicarbonyl Compounds

Significance

The authors reported that CBS ­reduction of 2,2-disubstituted cycloalkan-1,3-diones or hindered 2,2-disubstituted cyclic ketones using catecholborane as reductant proceeds with greater selectivity than when PhNEt₂ is added. ­After careful experiments, it is believed that the beneficial effect of this additive may be due to the ability of this amine to catalyze the conversion of a minor harmful impurity in catalyst preparations to the active catalyst.