title: DFT study on the cycloreversion of thietane radical cations.
abstract: The molecular mechanism of the cycloreversion (CR) of thietane radical cations has been analyzed in detail at the UB3LYP/6-31G* level of theory. Results have shown that the process takes place via a stepwise mechanism leading to alkenes and thiobenzophenone; alternatively, formal [4+2] cycloadducts are obtained. Thus, the CR of radical cations 1a,b(•+) is initiated by C2-C3 bond breaking, giving common intermediates INa,b. At this stage, two reaction pathways are feasible involving ion molecule complexes IMCa,b (i) or radical cations 4a,b(•+) (ii). Calculations support that 1a(•+) follows reaction pathway ii (leading to the formal [4+2] cycloadducts 5a). By contrast, 1b(•+) follows pathway i, leading to trans-stilbene radical cation (2b(•+)) and thiobenzophenone.
authors.affiliation: Departamento de Química Orgánica, Universidad de Valencia, Dr. Moliner 50, E-46100 Burjassot, Valencia, Spain. domingo@utopia.uv.es
authors.forename: Luis R
authors.initials: LR
authors.lastname: Domingo
authors.forename: Raúl
authors.initials: R
authors.lastname: Pérez-Ruiz
authors.forename: Juan E
authors.initials: JE
authors.lastname: Argüello
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Miranda
mesh_terms: D002412:Cations / Q000138:chemical synthesis / Q000737:chemistry; D003500:Cyclization; D005609:Free Radicals / Q000138:chemical synthesis / Q000737:chemistry; D015394:Molecular Structure; D011789:Quantum Theory; D013237:Stereoisomerism; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D002412:Cations; D005609:Free Radicals; D013438:Sulfhydryl Compounds