Cu(II)-mediated C-S/N-S bond formation via C-H activation: access to benzoisothiazolones using elemental sulfur.

A copper-mediated C-S/N-S bond-forming reaction via C-H activation that uses elemental sulfur has been developed. The addition of TBAI was found to be crucial for the success of this transformation. The method is scalable, shows excellent functional group tolerance, and is compatible with heterocycle substrates, providing efficient and practical access to benzoisothiazolones. The direct diversification of the benzoisothiazolone products into a variety of sulfur-containing compounds is also demonstrated.