A mechanistic investigation on the formation and rearrangement of silaspiropentane: A theoretical study.
The formation of silaspiropentane from addition of singlet silacyclopropylidene 1 and silacyclopropylidenoid 8 to ethylene has been investigated separately at the B3LYP, X3LYP, WB97XD, and M05-2X theories using the 6-31+G(d,p) basis set. The silacycloproylidenoid addition follows a stepwise route. In contrast, a concerted mechanism occurs for silacyclopropylidene addition. Moreover, the intramolecular rearrangements of silaspiropentane 9 to methylenesilacyclobutane 11 and 2-silaallene + ethylene 12 have been studied extensively. The required energy barrier for the isomerization of 9 to 10 was determined to be 44.0 kcal mol(-1) at the B3LYP/6-31+G(d,p) level. After formation of 10, the rearrangement to methylenesilacyclobutane 12 is highly exergonic by -15.9 kcal mol(-1), which makes this reaction promising. However, the conversion of 9 to 11 is calculated to be quite endergonic, by 26.5 kcal mol(-1).
Department of Chemistry, Faculty of Arts and Sciences, University of Aksaray, Aksaray, Turkey. cemburakyildiz@aksaray.edu.tr.
Cem Burak
CB
Yildiz
Department of Chemistry, Laboratory of Computational Chemistry, University of Balikesir, TR-10145, Balikesir, Turkey.
Akin
A
Azizoglu
Addition reaction; DFT; Silacyclopropylidene; Silacyclopropylidenoid; Silaspiropentane