The catalytic asymmetric Michael addition of α,β-unsaturated carbonyl compounds is one of the most valuable methods for constructing the β-carbon chirality centre because of its atom economy and efficiency. However, the catalytic asymmetric reverse α-addition of a nucleophile to an α,β-unsaturated carbonyl compound is much less common. Here we realize a palladium-catalysed asymmetric α-carboranylation of α,β-unsaturated carboxylic acids via an inverse electron-demand nucleophilic addition. The reaction features good B(9)-site selectivity of o / m -carboranes, precise α-regioselectivity towards α,β-unsaturated carboxylic acids, wide functional group tolerance and excellent enantioselectivities. A detailed reaction mechanism is proposed based on experimental and computational results that elucidates the origin of the enantioselectivity and α-selectivity. This finding has a guiding significance for the catalytic asymmetric anti -Michael-type addition of α,β-unsaturated carbonyl compounds and provides a different avenue for synthesizing α-chiral carboxylic acids.
Lei et al. (Fri,) studied this question.