Spontaneous trisulfide metathesis in polar aprotic solvents

Sulfur-sulfur bonds are ubiquitous across broad classes of natural products, peptides and proteins, drug molecules, and synthetic polymers and materials. The ability to make and break these bonds in a controlled manner is critical for their many scientific and technological applications. Here we report the discovery of an unusual S-S metathesis reaction of organic trisulfides. When exposed to certain polar aprotic solvents, trisulfides were found to undergo spontaneous metathesis, with the reaction equilibrium established in seconds in some cases. No exogenous reagents, heat, light or other stimuli were required to provoke this reaction. Furthermore, the trisulfide metathesis process can occur both inter- and intramolecularly. Understanding the scope and mechanism of this reaction enabled diverse applications of this chemistry in dynamic combinatorial library synthesis, the covalent modification of complex natural products, and S-S metathesis polymerization and depolymerization as a platform for chemically recyclable plastics.