PROTIODESILYLATION OF 3-TRIMETHYLSILYL-2-THIABICYCLO[2.2.1]HEPT-5-ENES AND DERIVATIVES - A STEREOCHEMICAL STUDY

endo- and hylsilyl-3-phenyl-2-thiabicyclo[2.2.1]hept-5-enes, the endo- trimethylsilyl-exo-S-oxide and their S,S-dioxide derivatives were prot iodesilylated with fluoride ion. Stereoconvergent reactions were found , affording the endo-phenyl derivatives. These results can be rational ised with the hypothesis of a common carbanionic intermediate. In cont rast, the desilylation of thylsilyI-3-exo-phenyl-2-thiabicyclo[2.2.1]h eptane gave a mixture of endo- and exo-isomers, thus proving the invol vement of the double bond in the control of the reaction stereoselecti vity.