Find the major product of the shown carvone reaction with the specified vinyllithium reagent in THF at −78°C, followed by KH at 25°C in THF/18-crown-6.
The vinyllithium reagent adds to the ketone carbonyl, producing an allylic alcohol after work-up. Deprotonation by KH creates a 1,5-dien-3-olate arranged for an anionic oxy-Cope [3,3] rearrangement. The carbon skeleton expands/reorganizes through the six-membered transition-state connectivity, and the product enolate gives a carbonyl on protonation. Following the two vinyl termini and substituents gives the medium-ring enone in A; simple aromatization or un-rearranged open-chain structures do not match the oxy-Cope bond changes.
More Pericyclic Reactions and Photochemistry: Electrocyclic, cycloaddition and sigmatropic reactions. Diels-Alder reaction, Claisen and Cope rearrangements and their applications in organic synthesis. FMO method of analysis. Woodward-Hoffmann rules. Photochemistry of alkenes, arenes and carbonyl compounds. Photo-oxidation and photo-reduction. Di-π-methane rearrangements, Norrish type-I and II reactions. Paternό-Büchi reaction, Photo- Curtius and Wolff rearrangements. Barton and Hofmann-Lӧffler-Freytag reactions. questions
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