Recent advances in C/N-alkylation with alcohols through hydride transfer strategies

Abstract

Recent advances in C/N alkylation using alcohols as alkylating reagents via hydrogen-shuttle methodologies: Borrowing Hydrogen, Acceptorless Dehydrogenative Coupling, and Base-mediated Hydride Transfer.

A general and expedient amination of alcohols catalysed by a single-site (NN)Co(ii)-bidentate complex under solventless conditions

“…To expand the substrate scope, we examined a comprehensive list of activated primary alcohols (benzyl alcohol analogs) and some inactivated aliphatic alcohols for selective N-alkylation of aniline (Table 4). Initially, the homologous series of linear pentanol to heptanol were dehydrogenated for alkylation with aniline, resulting in low yields of 39-47% (Table 4, products [56][57][58]. With an increase in the -CH 2units in linear alcohols, there was a slight increase in the yield of N-alkylated products.…”

“…40,42,43 However, there are very limited reports on cobalt-catalysed selective amine alkylation reactions [44][45][46][47][48][49][50][51][52][53][54] and BH C-C and C-N bond forming reactions. [55][56][57][58][59] Most of the molecular Co-complexes employed for catalytic N-alkylation of amines with alcohols are based on tridentate PNP or PNN ligand systems (Scheme 1). In 2015, Kempe and co-workers reported a PN 5 P ligand with triazine backbone stabilized Co(II)-PNP pincer complex employed for the efficient N-alkylation of both aromatic and aliphatic amines with alcohols.…”

Orthometallated Pd(ii) C^N^S pincer complex catalyzed sustainable synthesis of bis(indolyl)methanesviaacceptorless dehydrogenative coupling of alcohols

“…13 -C) . 1 H NMR (CDCl 3 , ppm): δ 10.11 (s, 1H), 7.67 (t, 3 J = 8 Hz, 3 J = 8 Hz, 6H), 7.48-7.37 (m, 14H), 7.21 (t, 3 J = 8 Hz, 3 J = 8 Hz, 1H), 7.08 (t, 3 J = 8 Hz, 3 J = 8 Hz, 1H), 6.37 (d, 3 J = 8 Hz, 1H), 5.97(s, 1H). 13…”

“…Nowadays, widely endurable and environmental friendly strategies are being investigated by synthetic chemists. 1 Further, the advancement of catalytic techniques for the direct transformation of C-H into C-X (X = C, O, N, S) bonds and the production of industrially essential compounds from simple starting materials have drawn significant attention in synthetic organic chemistry. 2 The largest and multifarious group of significant organic molecules is heterocyclic scaffolds.…”

“…13 C{1 H} NMR (100 MHz, DMSO-d 6 , ppm): δ 179.58, 165.93, 139.41, 132.50, 131.82, 128.42, 128.21, 127.88, 124.40, 123.62. Control experiments for mechanistic studies.…”