Nickel-Catalyzed Carbonylative Synthesis of α,β-Unsaturated Thioesters from Vinyl Triflates and Arylsulfonyl Chlorides

Abstract

A straightforward and efficient synthesis of α,β-unsaturated thioesters has been developed via a nickel-catalyzed thiocarbonylation reaction of vinyl triflates with arylsulfonyl chlorides. With Mo­(CO)6 as both CO source and reductant, a variety of α,β-unsaturated thioesters were obtained in moderate to good yields with very good functional group compatibility. It is noteworthy that the present method is the first example on nickel-catalyzed carbonylative synthesis of α,β-unsaturated thioesters by using arylsulfonyl chlorides as the coupling partner.

Synthetic Strategies for Versatile Thioester Building Blocks

“…In 2022, Qi, Wu and co-workers described a cascade method of Pd-catalyzed intramolecular Heck-type cyclization of aryl iodides having pendant alkene moiety (32) followed by thiocarbonylation, utilizing CO surrogate Mo(CO) 6 and arylsulfonyl chlorides (33) (Scheme 9). [20] This transformation allowed for the construction of benzo-fused five as well as sixmembered cyclic compounds (34) along with the formation of thioester functionality in moderate to good yields. As mentioned by the authors, Mo(CO) 6 was indispensable to afford thioesters (34), whereas no or low yield was obtained by CO gas or W(CO) 6 in lieu of Mo(CO) 6 , that attributes to the role of Mo(CO) 6 to efficiently reduce arylsulfonyl chlorides (33) to arylthiol analogues.…”

“…As proposed by the authors, aryl iodide having pendant alkene moiety (32) undergoes the oxidative addition to Pd(0) followed by pendant alkene insertion in intramolecular fashion to obtain a cyclized intermediate that subsequently engages at CO incorporation to form acyl palladium intermediate. The acyl palladium intermediate reacts with thiol, generated from aryl sulfonyl chloride upon reduction with Mo(CO) 6 , affording final product (34).…”

“…[20] This transformation allowed for the construction of benzo-fused five as well as sixmembered cyclic compounds (34) along with the formation of thioester functionality in moderate to good yields. As mentioned by the authors, Mo(CO) 6 was indispensable to afford thioesters (34), whereas no or low yield was obtained by CO gas or W(CO) 6 in lieu of Mo(CO) 6 , that attributes to the role of Mo(CO) 6 to efficiently reduce arylsulfonyl chlorides (33) to arylthiol analogues. In contrast to the previous reports, water exhibited detrimental effect on this reaction efficiency, leading to no thioester formation in the presence of water (2 equivalents).…”

“…Very recently, in 2022, Wu and co‐workers described nickel‐catalyzed thiocarbonylation of vinyl triflates ( 71 ) with sulfonyl chlorides ( 72 ) and Mo(CO) 6 to deliver a range of α,β‐unsaturated thioesters ( 73 ) in moderate to good yields (Scheme 19). [34] Various cyclic vinyl triflates showed proficiency in this transformation, despite linear vinyl triflates remained inert. As described by the authors, in this reaction diaryl disulfide intermediate is formed upon reduction of aryl sulfonyl chloride with Mo(CO) 6 and water played vital role improving the yield of diaryl disulfide intermediate as well as final α,β‐unsaturated thioester product.…”

A Visible Light Driven Nickel Carbonylation Catalyst: The Synthesis of Acid Chlorides from Alkyl Halides

“…The relatively high affinity of nickel to carbon monoxide is believed to inhibit carbonylation with these catalysts, requires high temperatures to overcome, and even with this often only proceeds with relatively activated aryl halide substrates (Figure 1a). [4–6] A number of important recent advances have been made in the use of more earth abundant nickel catalysts in carbonylations [5–12] . This includes key works in nickel catalysis by Skrydstrup, [7] Zhang, [8] Troupel [9] and others [10–12] that have shown how ligand design can be used to inhibit CO coordination in ketone synthesis.…”