Theory of cation-radical pericyclic reactions

Catalytic Hypervalent Iodine Promoters Lead to Styrene Dimerization and the Formation of Tri‐ and Tetrasubstituted Cyclobutanes

“…[7] In general, the oxidized form of an alkene (exemplified with 1a!A;S cheme 1) is proposed to react with another molecule of (unoxidized) alkene to form an oxidized cyclobutane intermediate (B)w hich then captures an electron to regain neutrality and form the product 2a.The source of the electron for the final step may be either the reduced form of the catalyst (i.e., as produced in the first step), or alternatively another molecule of alkene,t op ropagate the chain.…”

Surface photochemistry: Semiconductor mediated reactions of some saturated strained hydrocarbons

“…Haselbach suggests the lowering of the activation energy for Type C processes can be attributed to: (i) the shorter reaction coordinate; (ii) involvement of only one electron; and (iii) the reduced energy gap between the SOMO and the LUMO as compared to that of the HOMO and LUMO of the parent compounds (45). The MNDO calculations show a reduction in the reaction coordinate of 40% for the reaction of the radical cations.…”

“…The MNDO method has been successfully used by Bauld et al to study the reactivity of radical cations (45). Initial geometries of the neutral compounds were those of the MM2'IVANOV minimum energy conformation.…”

Conversion of unsaturated fatty acids - cycloadditions with unsaturated fatty acids [1]

“…Whilst formerly a concerted pericyclic process has been assumed [19], today there is evidence, that the reaction involves two steps with a radical cation as intermediate [20,21]. The initial olefin radical cation can be generated in three ways: electrochemically [21,22], by oxidation with aminium salts [23] or by photochemical electron transfer [17,23].…”