Asymmetric Hydrogenation of β-Aryl Alkylidene Malonate Esters: Installing an Ester Group Significantly Increases the Efficiency.
Qian-Kun ZhaoXiong WuLin-Ping LiFan YangJian-Hua XieQi-Lin ZhouPublished in: Organic letters (2021)
Herein, we report a practical method for efficient asymmetric hydrogenation of β-aryl alkylidene malonates. With a site-specifically tailored chiral spiro iridium catalyst, a series of β-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,β-unsaturated carboxylic esters significantly increased the efficiency of their asymmetric hydrogenation reactions.