Water as a direct proton source for asymmetric hydroarylation catalyzed by a Rh(I)−Diene: Access to nonproteinogenic β2/γ2/δ2-amino acid derivatives

A highly enantioselective rhodium-catalyzed intermolecular hydroarylation of α-aminoalkyl acrylates using water as a direct proton source has been realized by employing a chiral bicyclo[3.3.0] diene ligand, allowing efficient access to a broad range of α-aryl-methyl-substituted β-, γ-, and δ-amino esters with excellent enantioselectivities (up to 98% ee) under exceptionally mild conditions. By utilizing this method, a series of structurally interesting benzo-fused heterocyclic molecules and the corresponding β-, γ-, and δ-amino acids are facilely constructed.