Direct Nucleophilic Acylation with Acyllithium Reagents: Acyl Anion Synthons Unmasked

Organometallic intermediate-based organic synthesis: organo-di-lithio reagents and beyond

Metal-mediated organic reactions have become one of the great frontiers of organic synthesis.

Carbonylation of 1-lithiobutadiene with carbon monoxide followed by intramolecular acyllithiation of C═C double bond and intermolecular acylation with acid chloride: scope, applications, and mechanistic aspects

The carbonylation of a 1-lithio-1,3-butadiene derivative with CO gave rise to a butadienyl acyllithio intermediate, which underwent an immediate intramolecular acyllithiation of the C═C double bond, affording a lithio cyclopentadienyl enolate. The X-ray structural analysis of the enolate revealed a dimer connected with a "Li(2)O(2)" four-membered ring. Subsequent intermolecular acylation of this enolate with acid chlorides afforded β-keto-3-cyclopentenones, γ-keto-2-cyclopentenones, or cyclopentadienyl ester derivatives. The stereo- and regioselectivity of the in situ generated lithio cyclopentadienyl enolate with various acid chlorides was investigated and analyzed, showing that the formation of the above products was significantly dependent on both the substituents on the butadienyl skeleton and the bulkiness of acid chlorides.

Acyl-lithiation of olefins: formation of cyclopentenones from 1-lithio-butadienes and CO

[reaction: see text] Intramolecular acyl-lithiation of C=C double bonds proceeds following carbonylation of 1-lithio-1,3-dienes with CO to afford 2- or 3-cyclopentenone derivatives in good to excellent yields after hydrolysis. Addition of electrophiles to the carbonylation reaction mixtures affords various multiply substituted cyclopentenones.