Thiophostone-Derived Brønsted Acids in the Organocatalyzed Transfer Hydrogenation of Quinolines: Influence of the P-Stereogenicity



A new approach to Brønsted acid organocatalysis is described and is based on the use of thiophosphonic acids possessing both a chiral backbone and a chiral phosphorus function. The influence of the phosphorus stereochemistry on the enantioselectivity proved to be crucial in the hydrogen transfer hydrogenation of 2-phenylquinoline with Hantzsch esters.