Catalytic Asymmetric Hydrogenation of 3-Ethoxycarbonyl Quinolin-2-ones and Coumarins.

A protocol of iridium catalyzed asymmetric hydrogenation of 4-alkyl substituted 3-ethoxycarbonyl quinolin-2-ones and coumarins has been reported, providing a wide range of chiral dihydroquinolin-2-ones and dihydrocoumarins in high yields with excellent enantioselectivities (up to 99% ee) and high turnover numbers (up to 28 000). This efficient protocol was successfully applied for the synthesis of MPR3160 and the key chiral intermediate of R-106578.

Asymmetric Hydrogenation of ß-Aryl Alkylidene Malonate Esters: Installing an Ester Group Significantly Increases the Efficiency.

Herein, we report a practical method for efficient asymmetric hydrogenation of ß-aryl alkylidene malonates. With a site-specifically tailored chiral spiro iridium catalyst, a series of ß-aryl alkylidene malonate esters were hydrogenated to afford chiral malonate esters with good to excellent enantioselectivities (up to 99% ee) and high turnover numbers (up to 19000). The results showed that installing an ester group in α,ß-unsaturated carboxylic esters significantly increased the efficiency of their asymmetric hydrogenation reactions.