N-Aryl and N-Alkyl Carbamates from 1 Atmosphere of CO 2 .

Authors :: Takeuchi K
Chen MY
Yuan HY
Koizumi H
Matsumoto K
Fukaya N
Choe YK
Shigeyasu S
Matsumoto S
Hamura S
Choi JC
Source :: Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2021 Dec 23; Vol. 27 (72), pp. 18066-18073. Date of Electronic Publication: 2021 Dec 04.
Publication Year :: 2021
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) <subscript>2</subscript> /phen-catalyzed synthesis of organic carbamates from CO <subscript>2</subscript> , amines, and the reusable reactant Si(OMe) <subscript>4</subscript> . Density functional theory calculations revealed that the direct reaction of 1 with Si(OMe) <subscript>4</subscript> proceeds via a five-coordinate silicon intermediate, forming organic carbamates. Based on these results, the catalytic system was improved by using Si(OMe) <subscript>4</subscript> 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 <subscript>2</subscript> under atmospheric pressure.<br /> (© 2021 Wiley-VCH GmbH.)