Stannylation and Germylation of Some 4-, 5- and 6-Alkylcyclohex-2-enyl Chlorides

The allylic alcohols, trans-5-t-butylcyclohex-2-enol, trans-4-t-butylcyclohex-2-enol and trans-4- methylcyclohex-2-enol, have been converted into cyclohex-2-enyl chlorides by reaction with thionyl chloride and N-chlorosuccinimide-dimethyl sulfide. The stereochemistry of the allylic chlorides has been determined by 1H and 13C nuclear magnetic resonance spectroscopy. Stannylation of these chlorides with trimethyltinlithium, and triphenyltinlithium, has been examined and the resulting stannanes fully characterized by 1H, 13C and 119Sn n.m.r. spectroscopy, and electrophilic cleavage (acidolysis with deuterated trifluoroacetic acid) to the corresponding deuterocyclohexenes. A less extensive study of germylation (trimethylgermyllithium in hexamethylphosphoramide) was conducted also, and the allylic germanes fully characterized. Triphenyltinlithium and trimethylgermyllithium exhibit higher levels of stereo- and regio-specificity in chloride displacement than trimethyltinlithium