Tiolizis

Tiolizis, or thiolysis in English, is the chemical process in which a thiol acts as a nucleophile to cleave a bond in a target molecule. The reaction is named for the involvement of a thiol (or thiolate) and is used in various branches of chemistry and biochemistry. Common themes include the cleavage of carbon–heteroatom bonds or disulfide linkages, with sulfur-containing reagents serving as the attacking species.

In organic chemistry, thiolysis often proceeds via nucleophilic substitution or addition to electrophilic centers. A typical case is the thiolate attack on esters or thioesters, leading to cleavage of the acyl–oxygen or acyl–sulfur bond and formation of a new thioester plus an alcohol or carboxylate. Thiolysis can also refer to disulfide exchange, where a thiolate attacks a disulfide bond to yield a mixed disulfide and a liberated thiolate, enabling reshuffling of sulfur linkages.

In biochemistry and materials science, thiolysis is used to manipulate sulfur-containing linkages. For example, reducing disulfide bonds in proteins or polymers with thiol reagents (such as dithiols) is a common thiolysis-related transformation. Thiolysis also features in peptide and polymer degradation strategies, where cleaving linkages with thiols allows controlled breakdown under mild conditions.

Cautions and scope vary with substrate and conditions; thiolysis is distinct from hydrolysis or base-promoted saponification and relies on the reactivity of thiols or thiolates.