Gas-phase interaction of Me3Si+ ions withcis- andtrans-cyclohexanediols,their methyl ethers,and acetates

The effect of stereochemistry on the mechanism of gas-phase fragmentation of [M⁺SiMe₃]⁺ ions was studied usingcis- andtrans-1,2- and -1,4-cyclohexanediols, their methyl ethers, and acetates as model compounds. The higher stability of the [M⁺SiMe₃]⁺ions is characteristic of cis-isomers of all the compounds examined, which is associated with chelation in the case ofcis-cyclohexanediols andcis-methoxycyclohexanols and with the higher reactivity oftrans-isomers due to anchimeric assistance of the methoxy and acetoxy groups. Dehydration is characteristic of the [M⁺SiMe₃]⁺ ions formed from cyclohexanediols; both hydrogen atoms of the hydroxyl groups take part in the process, thus providing direct evidence of the chelation.Translated from Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 2025–2029, August, 1996.