N‐Aryl and N‐Alkyl Carbamates from 1 Atmosphere of CO<sub>2</sub>
Katsuhiko Takeuchi, Ming‐Yu Chen, Hao‐Yu Yuan, Hiroki Koizumi, Kazuhiro Matsumoto, Norihisa Fukaya, Yoong‐Kee Choe, Shinji Shigeyasu, Seiji Matsumoto, Satoshi Hamura, Jun‐Chul Choi
Abstract
Abstract We have successfully isolated and characterized the zinc carbamate complex (phen)Zn(OAc)(OC(=O)NHPh) ( 1 ; phen=1,10‐phenanthroline), formed as an intermediate during the Zn(OAc) 2 /phen‐catalyzed synthesis of organic carbamates from CO 2 , amines, and the reusable reactant Si(OMe) 4 . Density functional theory calculations revealed that the direct reaction of 1 with Si(OMe) 4 proceeds via a five‐coordinate silicon intermediate, forming organic carbamates. Based on these results, the catalytic system was improved by using Si(OMe) 4 as the reaction solvent and additives like KOMe and KF, which promote the formation of the five‐coordinated silicon species. This sustainable and effective method can be used to synthesize various N‐aryl and N‐alkyl carbamates, including industrially important polyurethane raw materials, starting from CO 2 under atmospheric pressure.