Catalytic Regio- and Enantioselective Boracarboxylation of Arylalkenes with CO₂ and Diboron

Catalytic asymmetric carboxylation of readily available alkenes with CO2, an abundant and sustainable one-carbon building block, that gives access to value-added alpha-stereogenic carboxylic acids in an atom- and step-economic manner is highly attractive. However, it has remained a formidable challenge for the synthetic community. Here, the first example of Cu-catalyzed highly regio- and enantioselective boracarboxylation reaction on various arylalkenes with diboron under an atmospheric pressure of CO(2 )is described, which afforded a variety of chiral beta-boron-functionalized alpha-aryl carboxylic acids with up to 87% yield and 97% ee under mild conditions. Importantly, alpha-substituted arylalkenes could also be subject to this protocol with excellent enantiopurities, thereby rendering an efficient approach for the generation of enantioenriched carboxylic acids with an alpha-chiral all-carbon quaternary center. Moreover, high functional group tolerance, scalable synthesis, and facile access to bioactive compounds, like (-)-scopolamine, (-)-anisodamine, and (-)-tropicamide, further demonstrated the synthetic utility of this strategy.