Rhodium-catalyzed asymmetric intramolecular addition of arylboronic acids to ketones: catalytic enantioselective access to 3-hydroxy-2,3-dihydrobenzofurans bearing a tetrasubstituted carbon stereocenter

A highly enantioselective rhodium-catalyzed intramolecular addition of arylboronic acids to unactivated ketones has been developed. By employing a simple, chiral sulfur-based branched olefin as the ligand, the reaction occurs efficiently under mild conditions. A wide range of chiral 3-hydroxy-2,3-dihydrobenzofurans bearing a tetrasubstituted stereocenter at C-3 position can be obtained in high yields (up to 98%) with excellent enantiomeric excesses (up to 98% ee).

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