Carvone- and Piperitone-Derived Allylic Stannanes and Aspects of Their Electrophilic Substitution

Abstract

cis - and trans- Carvotanacetols and - piperitols have been converted into the corresponding allylic chlorides, which were made to react with both trimethyltinlithium and triphenyltinlithium . The resulting allylic stannanes were characterized by ¹H, ¹³C and ¹¹⁹Sn n.m.r . spectroscopy, which permitted assignment of the relative configurations. Triphenyltinlithium appears to react in a (substantially) concerted fashion with the (optically active) chloride from the carvotanacetols yielding an optically active stannane . The corresponding trimethylstannane is optically inactive. Substitution reactions (S_E′) with acid and sulfur dioxide (in chloroform) are preferentially γ-anti and specifically γ- syn respectively, in line with conclusions based on other cyclohex-2-enyl systems.