cyclic NH lactams with a medium-size ring were hydrogenated smoothly, giving remarkably high enantioselectivities. The sulfur atom in the substrates did not bring an inhibition which was observed with commercially available bisphosphine ligands. This method was successfully applied in the scale-up synthesis of (R)-(-)-thiazesim.
Catalytic Enantioselective Synthesis of Protecting-Group-Free 1,5-Benzothiazepines
作者:Sara Meninno、Chiara Volpe、Alessandra Lattanzi
DOI:10.1002/chem.201700837
日期:2017.4.3
2,3‐dihydro‐1,5‐benzothiazepinones, by an organocatalyzed sulfa‐Michael reaction of readily available α,β‐unsaturated N‐acyl pyrazoles with 2‐aminothiophenols followed by silica‐gel‐catalyzed lactamization, has been developed. The method proceeds under mild conditions at room temperature and it requires only 1 mol % catalyst loading, to give 2‐aryl/alkyl‐substituted 1,5‐benzothiazepines in generally
from commercially available reagents to afford the desired product in high enantioselectivity. The reaction was compatible with a free amino group, thus allowing for expeditiousaccess to enantiomerically enriched 1,5‐benzothiazepines, which are important chemical entities in medicinal chemistry.