Understanding the Kinetics and Topological Events Within the Thione‐to‐Thiol Rearrangement of Xanthates

Abstract

AbstractThe heating of O‐furfuryl S‐methyl xanthate in p‐xylene solvent that is known from the literature to yield in parallel S‐furfuryl S‐methyl dithiocarbonate and furfuryl methyl sulfide via the thione‐to‐thiol rearrangement and carbon oxysulfide extrusion, respectively, have been studied theoretically. The CBS‐QB3 energies in conjugation with the solvation model density and B3LYP/6‐311G(2d,d,p) monodeterminantal wave functions have been used to investigate the kinetics of the parallel reaction by means of canonical transition state theory and molecular mechanism of the thione‐to‐thiol rearrangement by means of topological approaches. According to the supplied kinetic data the considered reactions are assisted strongly by the solvent molecules implying implicit solvent model cannot account properly the effect of solvent media. The cross topological analysis of the thione‐to‐thiol rearrangement via [1,3]‐sigmatropic rearrangement revealed that the electron density flow along the reaction is not concerted and the sequence of catastrophes can be summarized as 4‐EF†C‐0. In simple chemical term, chemical events through the reaction are heterolytic breaking of C−O bond, formation of pseudoradical center on the C atom, and creation of a new chemical C−S bond via the C‐to‐S coupling of pseudoradical centers, respectively.