Palladium-Catalyzed Linear Hydrothiocarbonylation of Unactivated Terminal Alkenes: Synthesis of Aliphatic Thioesters

Abstract

A Pd-catalyzed hydrothiocarbonylation of unactivated terminal alkenes is presented. According to this protocol, aliphatic thioesters were synthesized with exclusive linear selectivity under mild reaction conditions. Good to excellent yields (up to 91% yield), broad substrate scope, broad functional group tolerance, and utility of the method demonstrated the advantages of this protocol.

Synthetic Strategies for Versatile Thioester Building Blocks

“…In 2021, the same group discussed a Pd-catalyzed hydrothiocarbonylation of unactivated alkenes (9) with CO gas and free thiols (10) to afford thioester derivatives (11) in high linear selectivity (Scheme 3b). [13] Electron rich phosphine sulfoxide-(P-dialkyl)phosphine (SOP) (L3) ligand was critical for this transformation. As mentioned by the authors, the maintaining low reaction temperature was imperative to achieve high selectivity as the rise of temperature resulted in the enhancement of by-product formation, presumably the decreasing the solubility of CO gas upon increasing temperature.…”

“…However, due to the low binding affinity of electron rich alkenes to metal catalyst, catalytic hydrothiocarbonylation of unactivated aliphatic olefins posed considerable challenge. In 2021, the same group discussed a Pd‐catalyzed hydrothiocarbonylation of unactivated alkenes ( 9 ) with CO gas and free thiols ( 10 ) to afford thioester derivatives ( 11 ) in high linear selectivity (Scheme 3b) [13] . Electron rich phosphine sulfoxide‐(P‐dialkyl)‐phosphine (SOP) ( L3 ) ligand was critical for this transformation.…”

Palladium-Catalyzed Regiodivergent Decarboxylative Hydrothiocarbonylation of Vinylarenes Using Oxalic Acid Monothioesters

“…For -methylstyrene, the linear product was obtained in only 32% isolated yield (31). Although aliphatic alkene substrates were not amenable to achieve branched selectivity using conditions A in Scheme 2, they were suitable substrates for linear-selective hydrothiocarbonylation 14…”

“…For α-methylstyrene, the linear product was obtained in only 32% isolated yield ( 31 ). Although aliphatic alkene substrates were not amenable to achieve branched selectivity using conditions A in Scheme 2 , they were suitable substrates for linear-selective hydrothiocarbonylation 14 at room temperature. We demonstrated four examples including aliphatic alkene ( 35 , 38 ), vinyl silane ( 36 ), and vinyl boronate ( 37 ), all achieved high level of linear selectivity with l/b ratio larger than 20:1.…”

Visible Light-Accelerated Palladium-Catalyzed Thiocarbonylation Using Oxalic Acid Monothioester with Aryl/Alkenyl Sulfonium Salts

“…Therefore, the synthesis of thioesters has received a lot of attention from chemists. So far, the chemical synthesis of thioesters, in addition to the classical condensation reactions, usually employs transition metal-catalyzed thiocarbonylation of organohalogenates and hydrogen thiocarbonylation of unsaturated hydrocarbons . Not only these methods of synthesis of thioesters require the use of pungent-smelling thiols or thiophenols but also the reactions often need to be carried out under high temperature and pressure because of the involvement of carbon monoxide .…”