A Gaussian-2 molecular orbital study of the sigmatropic 1,3-hydrogen shift in 1-silapropene

Structures related to the sigmatropic 1,3-hydrogen shift rearrangement of 1-silapropene to vinylsilane have been located at the HF and the MP2(FU) levels with the 6-31G∗∗ basis set and characterized by MP2(FU)/6-31G∗∗ vibrational frequencies. The transition state structures found have been confirmed to connect 1-silapropene and vinylsilane by IRC calculations at the MP2(FU)/6-31G∗∗ level. The antarafacial and the suprafacial 1,3-hydrogen shifts in 1-silapropene are predicted to have nearly equal energy barriers, viz. 53.1 and 57.9 kcal mol−`, respectively, at the Gaussian-2 level, similar to the case of 1-phospharpropene.