Chiral BINOL-phosphoric Acid Research Articles

Direct enantioselective access to 4-substituted tetrahydroquinolines by catalytic asymmetric transfer hydrogenation of quinolines

A convenient protocol for the enantioselective synthesis of 4-substituted tetrahydroquinolines has been developed. Chiral BINOL phosphoric acids promote the reduction of a wide range of 4-substituted quinolines with Hantzsch esters with good to high levels of enantioselectivity.

Theoretical Study of the Mechanism of Hantzsch Ester Hydrogenation of Imines Catalyzed by Chiral BINOL-Phosphoric Acids

The mechanism of the Hantzsch ester hydrogenation of imines catalyzed by chiral BINOL-phosphoric acid has been investigated using DFT methods. Despite the importance of this reaction, there are a number of possible detailed mechanisms, and the preferred pathway has not been firmly established. Our calculations show that the catalyst not only activates the imine group for the reaction by acting as a Brønsted acid but also establishes an interaction with the Hantzsch ester that can lead to an explanation for the enantioselectivity.