Natural Product Glycine Betaine as an Efficient Catalyst for Transformation of CO₂ with Amines to Synthesize N-Substituted Compounds

Abstract

Transformation of carbon dioxide (CO 2 ) into value-added chemicals is of great importance, and use of natural products as a catalyst is very interesting. Herein, we used the naturally occurring glycine betaine as an efficient and renewable catalyst for the formation of a C−N bond between CO 2 and amines using PhSiH 3 as the reductant. The effects of different factors on the reaction were studied. It was demonstrated that the catalyst was very active for the reactions, and a broad range of amine substrates could be converted with satisfactory yields. Moreover, the selectivity to different N-substituted compounds could be controlled by the molar ratio of reactants (i.e., CO 2 , amines, and PhSiH 3 ) and the reaction temperature. In the catalytic cycle, the carbon oxidation state of CO 2 could be reduced to +2, 0, and −2, respectively, and thus, the corresponding formamides, aminals, and methylamines were produced via successive two-electron reduction steps.

Delineation of the Critical Parameters of Salt Catalysts in the N‐Formylation of Amines with CO2

“…F À . [10,11] An umber of salts including [TBA]F, [11] Cs 2 CO 3 , [19] glycine betaine, [40] zwitterionic P-ylide-CO 2 adducts [41] and various carboxylates [42] were proposed to act this way. [10] Based on these observations and the fact that [TBA]F can activate hydrosilanes in the reduction of carbonyls, [35][36][37][38][39] the activity of salt catalysts was attributed to the nucleophilicity of the anion and its ability to activate the hydrosilane reducing agent prior to CO 2 insertion.…”

Iron‐Rich Natural Mineral Gibeon Meteorite Catalyzed N‐formylation of Amines using CO2 as the C1 Source

“…Metal‐containing catalysts based on Pt, Re,, Ni, W, Cs,, Ru,, Rh, Ir, Pd, Au, Cu, Zn, Co and Fe,, have been reported for this reaction. In addition, a number of organocatalysts have also been reported, including 1,3,2‐diazaphospholene, N ‐heterocyclic carbenes (NHCs), N ‐heterocyclic olefins (NHOs), γ ‐valerolactone, triazabicyclodecene (TBD), glycine betaine, ionic liquids (ILs) and alkali carbonates ,. However, the recyclability and stability of these catalysts is often problematic, which hinders their transition to the industrial arena.…”

Mn‐Catalyzed Selective Double and Mono‐N‐Formylation and N‐Methylation of Amines by using CO2

“…Specifically,m ixtures of mono-a nd bis-formylated amines were obtainedi nt he presence of various catalysts, including Zn complexes, [4] N-heterocyclic carbenes, [5] glycineb etaine, [6] g-valerolactone, [7] and metal-organic frameworks. Recent advancesi nt his area have included formylation and methylation, as well as urea/urethane formation, based on innovative usage of organometallic and organocatalysts.…”

“…[1] Complementary to known formylation reactions, double N-formylation of primary amines providesb is-formylated amine products (N,N-diformylamines),w hich constitutes useful intermediates for drug discovery. Specifically,m ixtures of mono-a nd bis-formylated amines were obtainedi nt he presence of various catalysts, including Zn complexes, [4] N-heterocyclic carbenes, [5] glycineb etaine, [6] g-valerolactone, [7] and metal-organic frameworks. However,t hese methods have drawbacks of using harsh conditions and tedious synthetic procedures.…”

“…Recent studies [4,6,7,10,11] have indicated that N-formylation of amines might involve two main steps:1 )hydrosilylation of CO 2 to form silyl formatesf or the formation of formylated intermediates,a nd 2) reduction of formamidest op roduce the methylatedp roduct. Consistently, N-formyl-N-methylaniline 3p could be formed smoothly,a si ndicated in the reaction profile of amine 1p.I na ddition, 3p is rapidly consumed within six hours ( Figure S6).…”