SYNTHESIS AND STEREOCHEMISTRY OF ACIDOLYLSIS OF SOME CYCLOHEPT-2-ENYLSTANNANES AND -SILANES

Article abstract of DOI:10.1016/S0040-4020(01)86639-4

A range of methyl-substituted cyclohept-2-enyltrimethylstannanes and trimethylsilanes have been synthesized and characterised by ¹H, ¹³C and ¹¹⁹Sn (or ²⁹Si) nmr spectroscopy.Key conformational characteristics of some of these compounds are discussed.Acidolysis of these stannanes and silanes (with CF3COOD) proceeds cleanly to provide the ²H-substituted methylcycloheptene resulting from allylic rearrangement i.e. regiospecific γ-attack by the electrophile (S_E').Detailedexamination of the ²H nmr spectra of the methylcycloheptenes establishes a highly preferred, if not specific, γ-anti mode of electrophile delivery.Thus, this γ-anti-S_E' process may from the basis of synthetically useful applications in what is sometimes an awkward ring system for functionalization.