Selective N-formylation/N-methylation of amines and N-formylation of amides and carbamates with carbon dioxide and hydrosilanes: promotion of the basic counter anions of the zinc catalyst. Issue 23 (12th November 2020)

• Record Type: Journal Article
• Authors: Zhang, Qiao; Lin, Xiao-Tao; Fukaya, Norihisa; Fujitani, Tadahiro; Sato, Kazuhiko; Choi, Jun-Chul
• Is Part Of: Green chemistry. Volume 22:Issue 23(2020)
• Page Start: 8414
• Page End: 8422
• Publication Date: 2020-11-12
• Subjects: Environmental chemistry -- Industrial applications -- Periodicals; Environmental management -- Periodicals; 660
• DOI: 10.1039/d0gc02890h
• Languages: English
• ISSNs: 1463-9262

Abstract

Abstract : A Zn(OAc)2 catalyst bearing the 1, 10-phenanthroline (phen) ligand was efficient in the N -formylation of organic amine derivatives ( e.g., amines, amides, and carbamates) using carbon dioxide (CO2 ) and hydrosilanes. Abstract : A catalyst composed of commercially available Zn(OAc)2 and 1, 10-phenanthroline (phen) was effective in the N -formylation/ N -methylation of amines using CO2 as the C1 source in the presence of hydrosilanes. An equimolar reaction of N -methylaniline with PhSiH3 under a CO2 atmosphere yielded the N -formylation product in 92% yield at 25 °C. Scale-up of the reaction using 10 mmol substrate was also successful in affording the desired product in 83% yield (1.1 g). This catalyst exhibits a high thermal stability and a turnover number (TON) of 385 000 at 150 °C. In addition, the reaction of N -methylaniline in the presence of excess Ph2 SiH2 produced N, N -dimethylaniline. Furthermore, our catalytic protocol was developed for the N -formylation of amides and carbamates, which have smaller p K a values and lower reactivities than the corresponding amines. The present Zn(OAc)2 /phen catalyst was found to show versatility in the conversion of CO2 and amines into several functionalized organic chemicals under mild conditions. We propose that the basic counter anion ( i.e., the acetate) of the catalyst activates both the Si–H and N–H bonds.