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

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) /phen-catalyzed synthesis of organic carbamates from CO , amines, and the reusable reactant Si(OMe) . Density functional theory calculations revealed that the direct reaction of 1 with Si(OMe) proceeds via a five-coordinate silicon intermediate, forming organic carbamates. Based on these results, the catalytic system was improved by using Si(OMe) as the reaction solvent and additives like KOMe and KF, which promote the formation of the five-coordinated silicon species.

Sustainable Catalytic Synthesis of Diethyl Carbonate.

New sustainable approaches should be developed to overcome equilibrium limitation of dialkyl carbonate synthesis from CO and alcohols. Using tetraethyl orthosilicate (TEOS) and CO with Zr catalysts, we report the first example of sustainable catalytic synthesis of diethyl carbonate (DEC). The disiloxane byproduct can be reverted to TEOS.