tiolenereaksjonen

Tiolenereaksjonen, also known as the addition of thiols to alkenes, is a chemical reaction where a thiol (R-SH) adds across a carbon-carbon double bond of an alkene. This process typically occurs via a free radical mechanism or under acidic conditions. The free radical pathway is often initiated by peroxides or UV light, leading to the formation of a carbon radical that then reacts with the thiol. The Markovnikov or anti-Markovnikov addition of the thiol to the alkene can occur depending on the reaction conditions.

In the free radical addition, the radical initiator abstracts a hydrogen atom from the thiol, generating a thiyl radical (RS•). This thiyl radical then adds to the alkene double bond, forming a carbon radical. The carbon radical subsequently abstracts a hydrogen atom from another thiol molecule, propagating the chain reaction and yielding the thioether product. This mechanism often favors anti-Markovnikov addition, meaning the sulfur atom attaches to the less substituted carbon of the double bond.

Under acidic conditions, the reaction can proceed via an ionic mechanism. The alkene is protonated to form a carbocation, which is then attacked by the thiol acting as a nucleophile. This pathway typically follows Markovnikov's rule, where the sulfur atom attaches to the more substituted carbon of the double bond. Tiolenereaksjonen is a valuable synthetic tool for the formation of thioethers, which are important functional groups in organic chemistry and have applications in pharmaceuticals, materials science, and polymer chemistry.