N-heterocyclic carbene-catalyzed stereoselective cascade reaction: synthesis of functionalized tetrahydroquinolines.

The first N-heterocyclic carbene-catalyzed stereoselective aza-Michael-Michael-lactonization cascade reaction of 2'-aminophenylenones and 2-bromoenals for the construction of chiral functionalized tetrahydroquinolines with three consecutive stereogenic centers has been achieved in high yields (up to 98%) with excellent diastereo- (>25:1) and enantioselectivities (up to 98.7% ee).

Synergistic chiral ion pair catalysts for asymmetric catalytic synthesis of quaternary α,ß-diamino acids.

The combination of a chiral phosphate anion with a silver ion has been demonstrated as a powerful and synergistic ion pair catalyst for the aza-Mannich reaction. A series of valuable quaternary α,ß-diamino acid derivatives was obtained in high yield, and with excellent diastereo- (up to 25:1 dr) and enantioselectivity (up to 99% ee). The adducts can be smoothly transformed into the corresponding protected chiral quaternary α,ß-diamino acids by a one-pot hydrolysis reaction.