Microwave‐assisted Synthesis of Thioesters from Aldehydes and Thiols in Water

Abstract

We describe the synthesis of thioesters via copper‐ or iron‐catalyzed coupling of thiols with aldehydes on application of microwave irradiation. In this protocol, a variety of aliphatic and aromatic aldehydes and thiols were used, and the products were obtained in good to excellent yields.

Methods for the direct synthesis of thioesters from aldehydes: a focus review

“…Meanwhile, the reaction of complex A with the thiol 5 gives an iron(III) thiolate complex C, which after trapping the acyl radical B affords the expected thioester 6 and iron complex D. Finally, complex D reacts with HBr to regenerate FeBr 2 catalyst and complete the catalytic cycle (Scheme 2(b)). In their subsequent study, they considerably improved the efficiently of this transformation in the terms of yield and reaction time by performing the process under microwave irradiation [39].…”

Metal-free functionalization of SQs: a case of chemoselectivity and what ball-milling has got to do with it?

“…4 Thioesters can be traditionally obtained by acyl substitution reactions of carboxylic acids, acyl chlorides, and esters with thiols or disulfides. 5 However, new methodologies have been explored lately, including transition metal-catalyzed reactions (oxidative addition of thiols and disulfides to aldehydes, 6 carbonylation of alkenes and alkynes, 7 and Cu-promoted β-protonation of enals 8 ) or organocatalytic systems involving N-heterocyclic carbenes (NHCs). 9 Although several research reports have been published on the thioesterification process, they have some serious drawbacks including long reaction time and the need to use high temperatures or an oxidant.…”

Metal-free thioesterification of α,β-unsaturated aldehydes with thiols

“…These reactions are carried out in the presence of transition metal catalysts based on iron or copper and very often they are characterized by mediocre effectiveness, difficult reaction conditions and indispensable use of oxidants. [7][8][9] Alternatively, thioesters can be obtained in the presence of transition metal complexes as catalysts in thiocarbonylation of alkenes and alkynes 10,11 (Scheme 1b), although in most cases these processes require harsh conditions, like high temperatures and/or elevated pressures.…”