Ruthenium-Me-BIPAM-catalyzed addition reaction of aryl-boronic acids to benzofuran-2,3-diones for the enantioselective synthesis of 3-aryl-3-hydroxybenzofuran-2-ones

We have developed an enantioselective synthesis of 3-aryl-3-hydroxybenzofuran-2-ones via the ruthenium-catalyzed 1,2-addition of arylboronic acids to benzofuran-2,3-diones. The use of RuCl2(PPh3)(3) with a chiral bidentate phosphoramidite ligand [(R,R)-Me-BIPAM] in the presence of a small amount of acetonitrile (20 mol %) gave optically active 3-aryl-3-hydroxybenzofuran-2-ones with up to 96% ee. This reaction is the first example of a catalytic asymmetric 1,2-addition reaction of arylboronic acids to benzofuran-2,3-diones for the highly efficient and enantioselective synthesis of quaternary carbon containing benzofuran-2-ones. (c) 2015 Elsevier Ltd. All rights reserved.