Direct catalytic asymmetric Mannich-type reaction of a trichloromethyl ketone as a propionate equivalent donor is described. A new lanthanum aryloxide-iPr-pybox + lithium aryloxide combined catalyst was the most effective, promoting the reaction of N-2-thiophenesulfonyl imines with the trichloromethyl ketone. syn-Mannich adducts were obtained from various aryl, heteroaryl, alkenyl, and alkyl imines in > 99-72% yield, syn/anti of > 30:1-8:1, and 98-92% ee (from a propionate equivalent donor) using 2.5-10 mol % catalyst. The Mannich adduct was converted not only into ester but also into useful building blocks.
All Science Journal Classification (ASJC) codes
- Colloid and Surface Chemistry