Copper-PMHS System-Enabled Reductive Cyclization of o-Aminobenzamides with CO₂ as a Single-Carbon Synthon

Chemical utilization of carbon dioxide (CO₂) has emerged as a sustainable access for synthesizing high-value chemicals. Continuously designing the more practical reaction systems is of large importance. Herein, an unprecedented and powerful copper-PMHS reductive system of o-aminobenzamides with CO₂ is disclosed. Synthetically, a diverse range of quinazolinones (>70 examples) are rapidly assembled with excellent functional group tolerance in good yields. Moreover, building other types of heterocycles such as benzothiazoles and benzimidazoles is also allowable. Mechanistically, differing from the reported carbonylation cases, this finding represents a scarce example of CO₂ as a single-carbon atom synthon in the PMHS system.