Multiple bond migration with participation of a protophilic agent 4. Double bond migration in 3-methylthioprop-1-ene and 3-methoxyprop-1-ene: a comparative study
Vb. Kobychev et al., Multiple bond migration with participation of a protophilic agent 4. Double bond migration in 3-methylthioprop-1-ene and 3-methoxyprop-1-ene: a comparative study, RUSS CHEM B, 49(3), 2000, pp. 408-414
Ab initio study of the pathways of migration of the double bond in the 3-me
thylthioprop-1-ene (1) and 3-methoxyprop-1-ene (2) molecules with participa
tion of hydroxide ion was carried out by the RHF/6-31+G* and MP2/6-31+G//RH
F/6-31+G* methods, Conformational isomerism of the initial molecules and re
action products was considered. The distinctions are discussed in the spati
al and electronic structure of intermediate carbanions stabilized (for 1) d
ue to the negative hyperconjugation. Stationary points corresponding to com
plexes between the molecules under study and the hydroxide ion and between
the corresponding carbanion and water molecule were localized on the potent
ial energy surfaces of the proton transfer reactions. For 2, the single-sta
ge mechanism of prototropic rearrangement involving the H atom of the hydro
xide ion was found to be more energetically preferable than the two-stage m
echanism, whereas both mechanisms are expected to be equiprobable for 1.