Metal‐Free Catalyst for the Chemoselective Methylation of Amines Using Carbon Dioxide as a Carbon Source

Abstract

N-methylation of amines is an important step in the synthesis of many pharmaceuticals and has been widely applied in the preparation of other key intermediates and chemicals. Therefore, the development of efficient methylation methods has attracted considerable attention. In this respect, carbon dioxide is an attractive C1 building block because it is an abundant, renewable, and nontoxic carbon source. Consequently, we developed a highly chemoselective, metal-free catalytic system that operates under ambient conditions for the N-methylation of amines.

Sustainable conversion of carbon dioxide: the advent of organocatalysis

“…The organocatalyzed N-methylation of amines using CO 2 and suitable reducing agents (hydroboranes) has recently emerged as another attractive catalysis route towards CO 2 valorisation. Contributions from Cantat et al 143 and Dyson and co-workers 144 have set the stage for new conversions mediated by proazaphosphatrane superbases and NHC based organocatalysts. The results highlight the versatile catalytic use of NHCs towards the conversion of CO 2 into a variety of organic molecules such as alkylated amines, MeOH, formamidines and organic carbonates.…”

Catalyst-free N-methylation of amines using CO2

“…Subsequently, Cantat and co-workers reported the first metal-free methylation of amines by using phosphorus base as catalyst. 8 In recent years, methylation of amines with CO 2 based on metal catalysts 6, 9-13 and organocatalysts 8,[14][15][16] have been developed as shown in Scheme 1.…”

In Situ Generation of an N‐Heterocyclic Carbene Functionalized Metal–Organic Framework by Postsynthetic Ligand Exchange: Efficient and Selective Hydrosilylation of CO2

“…[7] Ying and co-workers reported the first example of NHC-catalyzed reduction of CO 2 with silanes to form methoxide products along with siloxane (Ph 2 (MeO)SiO-) n via formoxysilane intermediates. [7] Ying and co-workers reported the first example of NHC-catalyzed reduction of CO 2 with silanes to form methoxide products along with siloxane (Ph 2 (MeO)SiO-) n via formoxysilane intermediates.…”

“…[10] Accordingly,t he high degree of control over the structural and chemical features makes MOFs extremely promising as next-generation CO 2 capture materials, [11] and their ability to promote catalytic conversion of CO 2 into high-value chemicals has been demonstrated. [12,13] To date,o nly two MOF-based catalysts have been reported to successfully realize chemical reduction of CO 2 to either methanol [14] or other related intermediates (HCO 2 H), [15] but both require harsh reaction conditions, including elevated operating temperature (up to 250 8 8C) and high CO 2 pressure (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). [12,13] To date,o nly two MOF-based catalysts have been reported to successfully realize chemical reduction of CO 2 to either methanol [14] or other related intermediates (HCO 2 H), [15] but both require harsh reaction conditions, including elevated operating temperature (up to 250 8 8C) and high CO 2 pressure (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15).…”