Efficient and Enantioselective Rhodium(I)-Catalyzed Arylation of α-Ketoesters: Synthesis of (S)-Flutriafol

An enantioselective addition of arylboronic acids and α-ketoesters promoted by a Rhodium(I)-chiral diene catalyst is reported. The transformation proceeds regioselectively in the presence of as low as 0.5 mol% of the catalyst generated in situ from a Rhodium(I) salt and diene L1, which is a bicyclo[2.2.1] ligand scaffold bearing 2,5 dinaphthyl substituents, to afford tertiary chiral α-hydroxy esters with high stereoselectivities (90–99% ee's) and in 50–>99% yields. The method provides an expeditious and enantioselective synthesis of (S)-flutriafol. (Figure presented.).