Protiodesilylation of 3-trimethylsilyl-2-thiabicyclo[2.2.1]hept-5-enes and derivatives: A stereochemical study

Article abstract of DOI:10.1016/0040-4020(96)00032-4

endo- and exo-trimethylsilyl-3-phenyl-2-thiabicyclo[2.2.1]hept-5-enes, the endo-trimethylsilyl-exo-S-oxide and their S,S-dioxide derivatives were protiodesilylated with fluoride ion. Stereoconvergent reactions were found, affording the endo-phenyl derivatives. These results can be rationalised with the hypothesis of a common carbanionic intermediate. In contrast, the desilylation of 3-endo-trimethylsilyl-3-exo-phenyl-2-thiabicyclo[2.2.1]heptane gave a mixture of endo- and exo-isomers, thus proving the involvement of the double bond in the control of the reaction stereoselectivity.