Cu-Catalyzed Oxidative Thioesterification of Aroylhydrazides with Disulfides

Abstract

An alternative thioesterification reaction via coppercatalyzed oxidative coupling of readily available aroylhydrazides with disulfides is developed, in which oxidative expulsion of N 2 overcomes the activation barrier between the carboxylic acid derivatives and the products. The reaction produces various thioesters in good to excellent yields with good functional group tolerance. In the reaction, stable and easily available aroylhydrazides are used as acyl sources and the relatively odorless disulfides are used as S sources. Mechanistic investigations demonstrate that the reaction of copper salt and oxidant (NH 4 ) 2 S 2 O 8 allows for achievement of tandem processes, including deprotonation, free-radical-mediated denitrogenation, and C−S bond formation.

Ni-Catalyzed Aryl Thioester Synthesis via Thioester Transfer Reaction

“…The residue was purified with column chromatography (petroleum ether/ethyl acetate, V∶V＝50∶1) on silica gel to give pure product 3. Among them, 3a [15] , 3b [15] , 3d [15] , 3g [22] , 3h [16] , 3i [15] , 3k [15] , 3m [18] , 3n [20] , 3p [21] and 3d [15] are known compounds.…”

A Recent Progress for the Synthesis of Thiocarboxylates

“…Dong [44] reported the copper-catalyzed oxidative coupling of benzohydrazides with disulfides, in which the oxidative exclusion of N 2 overcame the activation barrier between carboxylic acid derivatives and products (Scheme 20). Mechanistically, there were two ways to generate acyl radical 91: 1) Oneelectron was transferred between aroyl hydrazide 86 and copper(II) species generated cation radical 87, which underwent a series of transformations (88)(89)(90) to generate acyl radical 91 (major).…”

PhI(OAc)2-mediated C–N bond cleavage of acylhydrazines with amines for the synthesis of amides

“…Acylhydrazines are stable compounds and widely used as synthons for the preparation of pharmaceuticals, agrochemicals, polymers and peptides. 24 In recent work, the amination of acylhydrazines via C–N bond cleavage for the synthesis of amides provided an efficient and attractive method; 25 however, the aliphatic primary amines and secondary amines could only afford the corresponding amides in trace amounts in this reaction system, and in addition, a metal catalyst was used in the system. Herein, we report a metal-free efficient protocol for the preparation of amides via amidation of acylhydrazines via PhI(OAc) 2 -mediated C–N bond cleavage (eqn (1)).…”