Isomerization of an isolable silylene into a silene via 1,2-silyl migration

A kinetic study of the thermal irreversible isomerization of an isolable dialkylsilylene into the corresponding cyclic silene revealed that the activation enthalpy (ΔH^‡) and entropy (ΔS ^‡) are 18.49 ± 0.43 kcal mol^-1 and -20.32 ± 1.35 cal mol^-1 K^-1, respectively. The relatively low ΔH^‡ and negative ΔS^‡ values are in accord with the concerted 1,2-silyl migration via a cyclic transition state as previously proposed. The cyclic silene in benzene-d₆ isomerized photochemically into the corresponding alkenylsilane via 1,3-hydrogen shift.