Chiral bis-trifluoromethanesulfonylamide as a chiral Brønsted acid catalyst for the asymmetric hetero Diels-Alder reaction with Danishefsky's diene

Bis-trifluoromethanesulfonylamide (bis-triflylamide) itself works as an efficient chiral Brønsted acid catalyst for the hetero Diels-Alder reactions between Danishefsky's diene and glyoxylate or phenylglyoxal presumably through double hydrogen bonding.