Conjugate addition of trinethyltinlithium to cyclohex-2-enone followed by enolate trapping with alkylating agents provide traus-2-alkyl-3-trimethylstannylcyclohexanones, which on reaction with Grignard reagents derived from 4-bromo-1-butene or 5-bromo-1-pentene afford tertiary γ-stannylcyclohexanols in a highly diastereoselective fashion. Triaethylstannyl- triggered ring fragmentation (by lead tetraacetate in benzene) leads efficiently to dienones ...
![2,9-dimethyl-1,10-dioxaspiro[4.5]decane Structure](https://image.chemsrc.com/caspic/070/73208-58-9.png)