Molecular Transformation Based on an Innovative Catalytic System

Abstract

Novel innovative catalytic systems such as hydrogen-bond donors and thiourea hybrid catalysts have been developed for the asymmetric synthesis of biologically important pharmaceuticals and natural products. Benzothiadiazines possess a stronger hydrogen-bond donor ability compared to thioureas and exhibit remarkable catalytic performance for the activation of α,β-unsaturated amides. Hybrid thioureas (bearing an arylboronic acid and an ammonium salt) efficiently promote the hetero-Michael addition to α,β-unsaturated carboxylic acids and the O-alkylation of keto enols with 5-chlorofuran-2(5H)-one. These hybrid catalysts enable the first total synthesis of non-racemic avenaol, a noncanonical strigolactone, as well as the asymmetric synthesis of several pharmaceuticals. In addition, this study discovers unique chemical phenomena (i.e., the dual role of benzoic acid as a boron ligand and a proton shuttle, the chirality switch of products by solvent used, and the dynamic kinetic resolution of a racemic electrophile in an S N 2-type reaction).

Thiourea catalysts for synthesis of Active Pharmaceutical Ingredients

“…Applications of thiourea catalysts for synthesis of Active Pharmaceutical Ingredients (API). 13 Aza-Michael addition reaction is a classical method for synthesizing β-amino acids. Takemoto and co-workers explored the possibility of intermolecular aza-Michael addition of benzylhydroxylamine to carboxylic acids 2 using the hybrid thiourea catalyst 1.…”