Quantum-chemical investigation of the mechanisms of nucleophilic addition reactions to acetylene

The interactions between an acetylene molecule and lithium hydrosulfide in the dissociated and undissociated states have been calculated in the framework of the semiempirical MNDO method. It has been established that acetylene can easily form molecular complexes with lithium hydrosulfide, which are stable toward all the possible types of nonradical dissociation. A comparison with the previously considered reaction between C₂H₂ and LiOH shows that in the case of LiSH, the activation barriers to the isomerization of the complex C₂H₂·LiSH to vinyl mercaptans are considerably lower.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1792–1796, August, 1989.