Copper-Catalyzed Vicinal Chloro-thiolation of Alkynes with Sulfonyl Chlorides

Abstract

A copper-catalyzed vicinal chloro-thiolation of alkynes with inexpensive and diversified sulfonyl chlorides RSO 2 Cl (R = aryl, alkyl) has been developed. This practical and scalable reaction could be used for the construction of a number of unexplored bioactive chlorothiolated alkenes. Internal alkynes could also undergo the chloro-thiolation to provide tetrasubstituted alkynes. Preliminary mechanistic investigations revealed a plausible radical process involving a sulfur-centered radical intermediate via copper-mediated homolysis of the S−Cl bond.

Synthesis of Thioethers from Sulfonyl Chlorides, Sodium Sulfinates, and Sulfonyl Hydrazides

“…In 2018, Yi and co-workers 30 designed a CuCl-catalyzed chlorothioetherification of alkynes with alkane-and arenesulfonyl chlorides in the presence of PPh 3 and DMF (Scheme 5). Free-radical trapping experiments using 4 equiv TEMPO did not give the desired products 7, suggesting that a radical process is involved in this reaction and that most of the target product is produced via such a process.…”

Hybrid Reaction Systems for the Synthesis of Alkylated Compounds Based upon Cu‐Catalyzed Coupling of Radicals and Organometallic Species

“…For example, chloro-thiolation of alkyne 19.1 to give chlorothiolated alkene 19.3 is catalyzed by a copper catalyst in the presence of stoichiometric amounts of PPh 3 and sulfonyl chloride 19.2 (Scheme 19). [29] In the catalytic cycle, PPh 3 acts as a reductant for sulfonyl chloride 19.2 to give a sulfenyl chloride intermediate. Chlorocupration of alkyne 19.1 gives the corresponding vinylic copper which reacts with the sulfenyl radical via an addition-elimination process to yield the product.…”

Silver-catalyzed synthesis of β-fluorovinylphosphonates by phosphonofluorination of aromatic alkynes

“…Among the strategies for constructing diverse alkenes containing two-heteroatom bonds, such as disulfonylation [14][15][16], heterohalogenation [17][18][19][20], bis(trifluoromethyl)thiolation [21], and phosphorylation [22], the direct heterodifunctionalization of alkynes using three-component reactions is the most rapid and convenient one (Scheme 1). Although studies on alkyne difunctionalization are ongoing [23], the successful attachment of a fluorine atom to the resulting alkene through transition metal catalysis remains a challenge.…”