Diastereoselective Pomeranz–Fritsch–Bobbitt synthesis of (S)-(−)-salsolidine using (R)-N-tert-butanesulfinylimine as a substrate
摘要:
The highly diastereoselective addition of methyl Grignard reagent to chiral (R)-N-tert-butanesulfinylimine 8 was the key step in the synthesis of (S)-(-)-salsolidine 1 of high enantiomeric purity. The resulting addition product, tert-butanesulfinylamide 9, was then subjected to cyclization via amine 10 and Pomeranz-Fritsch aminoacetal 11. (c) 2006 Elsevier Ltd. All rights reserved.
Chiral Brønsted Acids Catalyze Asymmetric Additions to Substrates that Are Already Protonated: Highly Enantioselective Disulfonimide-Catalyzed Hantzsch Ester Reductions of NH–Imine Hydrochloride Salts
作者:Benjamin List、Vijay N. Wakchaure、Carla Obradors
DOI:10.1055/s-0040-1706413
日期:2020.10
are frequently used substrates in asymmetric Bronsted acid catalysis, their corresponding salts are generally considered unsuitable reaction partners. Such processes are challenging because they require the successful competition of a catalytic amount of a chiral anion with a stoichiometric amount of an achiral one. We now show that enantiopure disulfonimides enable the asymmetric reduction of N–H imine