Enantioselective Construction of Chiral 2,3-cis-Dimethyldihydrobenzofuran with an All-Carbon Quaternary Center: An Efficient Approach to (+)/(-)-PI-220 and (+)-3-epi-Furaquinocin C

A new strategy for the enantioselective construction of chiral 2,3-cis-dimethyldihydrobenzofurans has been developed by a ruthenium-catalyzed asymmetric hydrogenation of racemic -aryloxybutanone via dynamic kinetic resolution (DKR), combined with a palladium-catalyzed intramolecular reductive Heck cyclization. Starting from optically active 2,3-cis-dimethyldihydrobenzofuran, the natural products (+)/(-)-PI-220 and (+)-3-epi-furaquinocin C were synthesized in high yields.