Ru-mediated and sulfur-directed ortho-C-H activation of benzyl thioethers with internal alkynes and selective hydro-thiolation of acetylene dicarboxylates

In this report, we have established a Ru(η6-C6H6)Cl2 catalyzed ortho-C-H activation of benzylthioethers with alkynes under milder reaction conditions. The sulfur atom of benzyl thioethers worked as directing group for ortho-C-H activation of benzylthioethers. The reaction was found to be well tolerated towards a range of benzylthioethers as well as alkynes. Moreover, the reaction is significantly influenced by the length of alkyl and aryl thioether, while the best results were obtained with benzyl thioethers. Kinetic isotopic experiments suggest that the ortho-C-H bond breaking is not a rate-determining step for present reaction. Apart from ortho-CH activation, under the same reaction conditions, a selective debenzylative hydro-thiolation was exclusively obtained with acrylates, which broadens the synthetic impact of benzylthioethers for the preparation of mixed chalcogen ethers. Moreover, it is an unusual observation and not yet reported.

Publication History

Received: 11 April 2024

Accepted after revision: 19 June 2024

Accepted Manuscript online:
19 June 2024