Catalyst- and solvent-free efficient access to N-alkylated amines via reductive amination using HBpin

Abstract

A general method for catalyst- and solvent-free room temperature reductive amination has been developed and it efficiently delivers a wide range of sterically and electronically diverse secondary amines in one-pot.

A metal-free protocol for the preparation of amines using ammonia borane under mild conditions

“…Transfer hydrogenation offers an alternative pathway that avoids the use of pressurized gas or the need of specialized equipment. 29,30 In this respect, great efforts have been made using hydrosilanes, [31][32][33][34][35][36] borohydrides 37,38 or formic acid and derivatives [39][40][41][42] as the hydrogen source for reductive amination reactions. Although these procedures offer many benefits and show interesting substrate scope, there remain challenges such as the use of water-soluble substrates, highly functionalized compounds, metal contamination of products and so on.…”

Solvent-free mechanochemical grinding facilitates clean synthesis of N-substituted amines

“…1 In organic synthesis, a significant part of the organic material as a reactant is ideally consumed and converted into products; however, pollution and energy consumption remain a major concern, particularly in scalable synthesis. As such, solvent-free reactions 2,3 have emerged as an interesting area that facilitates a wide range of atom-economical chemical reactions without the use of volatile and toxic solvents, hazardous reactants, and toxic catalysts with minimized waste production. 4,5 In this line, mechanochemical grinding (i.e., solid-solid) procedures minimize the chemical waste and provide viable and feasible support for solvent-free chemical reactions.…”

“…CDCl 3 ) δ 8.28 (d, J = 2.4 Hz, 1H), 7.62 (dd, J = 8.2, 2.4 Hz, 1H), 7.30 (t, J = 10.8 Hz, 3H), 7.21 (d, J = 8 3. Hz, 2H), 3.47 (s, 4H), 2.45 (s, 8H), 1.30 (s, 9H).13 C NMR (101 MHz, CDCl 3 ) δ 150.2, 139.6, 134.9, 132.9, 129.0, 125.2, 124.0, 62.7, 59.4, 53.1, 34.5, 31.5; HRMS (ESI) m/z: [M + H] + Calcd for C 21 H 29 ClN 3 358.2045; found 358.2049.…”

A Catalyst and Solvent Free Route for the Synthesis of N‐Substituted Pyrrolidones from Levulinic Acid

“…HBpin is a well-known and relatively inexpensive reagent used for reductive amination [29][30] and other reactions. [31][32] However, to date its utility for the synthesis of pyrrolidones remains unexplored.…”