Cobalt carbonyl catalyzed reaction of mercaptans with Schiff bases and carbon monoxide

Abstract

Thiophenols and p-methylbenzyl mercaptan react with Schiff bases and carbon monoxide in benzene, in the presence of cobalt carbonyl, to give amides as the principal products. These amides arise from cleavage of the carbon–nitrogen double bond of the reactant imine. The reaction is applicable to a variety of Schiff bases (i.e. aliphatic, benzylic, aromatic). Thioesters and olefins are usually obtained as reaction by-products.

Cobalt catalysed aminocarbonylation of thiols in batch and flow for the preparation of amides

“…The plausible mechanism of this reaction is outlined in Scheme 2 . Following Alper's proposal, 5 the thiol splits the cobalt carbonyl complex giving A, which incorporates a CO unit (B) and eliminates COS to produce intermediate C. A new CO insertion gives D which is attacked by the amine to yield the final amide plus one cobalt anionic species which, combined with the hydride released in the first step, regenerates the catalyst.…”

“…4 In 1986 Alper et al described a synthesis of amides from thiols, imines and CO mediated by Co 2 (CO) 8 . 5 The reaction conditions were harsh: high CO pressure (55 to 66 atm), and high temperature (180 C) for 12 hours. The desired amide was isolated in moderate yields (30-59%) together with a thioester, a secondary amide and the disulde of the starting thiol.…”

Reactions of Acylpalladium Derivatives with Oxygen, Nitrogen, and Other Group 15, 16, and 17 Atom Nucleophiles: Intermolecular Processes: Palladium-Catalyzed Hydrocarboxylation and Related Carbonylation Reactions ofπ-Bonded Compounds

“…Transition-metal-catalyzed carbonylation reactions of sulfur-containing compounds and the thiocarbonylation of thiols to various substrates [57 ]- [60] have been extensively developed during the past decade. Sulfur-containing compounds have long been considered as poisons of many noble metal catalysts due to their strong coordinating and adsorptive properties, which cause them to block the reactive sites of metals.…”

“…[61] In fact, there have been relatively few investigations of metal-catalyzed synthetic reactions involving organosulfur compounds as reactants. [57 ]- [60] Recently, the carbonylation of dienes in the presence of thiophenol was achieved to give ␤,␥-unsaturated thioesters in fine yields. [62] The regioselectivity of the reaction depends mainly on steric factors of the dienes forming either the 1,2-or 1,4-products of addition with E-isomers predominant in all cases ( Table 1).…”