Synthesis of Symmetric and Unsymmetric Secondary Amines from the Ligand-Promoted Ruthenium-Catalyzed Deaminative Coupling Reaction of Primary Amines. J Org Chem 2018 May 04;83(9):4932-4947
Date
04/19/2018Pubmed ID
29665681Pubmed Central ID
PMC5998338DOI
10.1021/acs.joc.8b00649Scopus ID
2-s2.0-85046353021 (requires institutional sign-in at Scopus site) 27 CitationsAbstract
The catalytic system generated in situ from the tetranuclear Ru-H complex with a catechol ligand (1/L1) was found to be effective for the direct deaminative coupling of two primary amines to form secondary amines. The catalyst 1/L1 was highly chemoselective for promoting the coupling of two different primary amines to afford unsymmetric secondary amines. The analogous coupling of aniline with primary amines formed aryl-substituted secondary amines. The treatment of aniline- d7 with 4-methoxybenzylamine led to the coupling product with significant deuterium incorporation on CH2 (18% D). The most pronounced carbon isotope effect was observed on the α-carbon of the product isolated from the coupling reaction of 4-methoxybenzylamine (C(1) = 1.015(2)). A Hammett plot was constructed from measuring the rates of the coupling reaction of 4-methoxyaniline with a series of para-substituted benzylamines 4-X-C6H4CH2NH2 (X = OMe, Me, H, F, CF3) (ρ = -0.79 ± 0.1). A plausible mechanistic scheme has been proposed for the coupling reaction on the basis of these results. The catalytic coupling method provides an operationally simple and chemoselective synthesis of secondary amine products without using any reactive reagents or forming wasteful byproducts.
Author List
Arachchige PTK, Lee H, Yi CSAuthor
Chae Yi PhD Professor, Inorganic and Organometallic Chemistry, Homogeneous Catalysis in the Chemistry department at Marquette UniversityMESH terms used to index this publication - Major topics in bold
AminesCatalysis
Chemistry Techniques, Synthetic
Ligands
Ruthenium
Stereoisomerism
