Rapid Access to a Series of Highly Functionalized α,β-Unsaturated Cyclopentenones. A Caveat on Aminospirocyclization

Article abstract of DOI:10.1021/jo00380a019

Conjugate addition of a series of functionalized aryllithium reagents to cyclopentenyl sulfones 9 and 17 results in α-sulfonyl anion intermediates taht are further alkylated to afford triply converged adducts 12a-c and 19.Refunctionalization of these adducts provides α,β-unsaturated cyclopentenones 4a-c and 21 in high overall yields.Attempted intramolecular Michael addition of these (γ-aminopropyl)cyclopentenones to produce the spiro <4.4> ring system was unsuccessful.