Efficient Rh-Catalyzed Chemo- and Enantioselective Hydrogenation of 2-CF 3 -Chromen/Thiochromen-4-ones.

A Rh-catalyzed highly chemo- and enantioselective hydrogenation of 2-CF 3 -chromen/thiochromen-4-ones was successfully established achieving excellent selectivity and high turnover numbers. Under mild conditions, a series of 2-CF 3 -chromen-4-ones were hydrogenated to provide the corresponding chiral 2-CF 3 -chroman-4-ones with excellent enantioselectivities (up to 99.9% ee) and achieve high turnover numbers (TON of up to 11,800). Moreover, the obtained hydrogenation products were also successfully transformed into other derivatives including the important intermediate of plasmepsin inhibitors with maintained enantiopurity.