55. One-Pot Methylenation Cyclization Employing Two Molecules of CO2 with Arylamines and Enaminones

Zhao, Y.*; Liu, X.; Zheng, L.; Du, Y.; Shi, X.; Liu, Y.; Yan, Z.*; You, J.*; Jiang, Y.*  J. Org. Chem. 2020, 85, 912-923. Download Link

Abstract: One-pot methylenation−cyclization employing two molecules of CO2 with enaminones and primary aromatic amines was discussed for the first time to access cyclized products. This 1,5,7-triazabicyclo[4.4.0]dec-5-ene and ZnCl2- catalyzed procedure was characterized by the selective conversion of two molecules of CO2 into methylene groups in a multicomponent cyclization reaction. According to the computational study and control experiments, the reaction might proceed through the generation of bis(silyl)acetal and condensation of arylamine and aza-Diels−Alder processes. Moreover, the resulting products will probably be potential organic building blocks with adjustable photophysical properties.