title: A plethora of carbene interconversions on the C(5)H(4)S energy surface: a computational study.
abstract: The potential energy surface for the reaction of atomic carbon with thiophene has been studied computationally. Intermediates which are energetically viable include the 2- and 3-thienylcarbenes 8 and 11, thiacyclohexa-3,5-dien-2-ylidene, 10, and thiacyclohexa-2,3,5-triene, 6. In accord with experimental data, 6 and 8 are in equilibrium. The lowest-energy pathway for rearrangement of 6 to 8, which is endothermic by 14.5 kcal/mol, involves ring opening to Z-2-penten-4-ynthial which then recloses to carbene 8. A 1,4 addition of C across the diene system in thiophene generates an ylid which rearranges with little or no barrier to cyclopentadienethione, the global minimum on this potential energy surface.
authors.affiliation: Department of Chemistry, Auburn University, Auburn, Alabama 36849, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: McKee
authors.forename: P B
authors.initials: PB
authors.lastname: Shevlin
authors.forename: M
authors.initials: M
authors.lastname: Zottola