A Generic and Reproducible Route to Homo- and Heteroannular Bicyclic β-Diketones via Knochel-Type 1,4-Conjugate Additions to α,β-Unsaturated Cycloalkenones

A generic and reproducible method for the preparation of homo- and heteroannular bicyclic β-diketones is reported. The method employs the copper acetate mediated 1,4-conjugate addition of organozinc derivatives of iodopropionate and iodobutanoate esters to α,β-unsaturated cycloalkenones, followed by intramolecular Dieckmann condensation.