Alkylation of enolate anions with dimethyl 3-bromo-2-ethoxypropenylphosphonate. A convergent cyclopentenone annulation method

Article abstract of DOI:10.1139/v82-166

A new convergent synthesis of 2-cyclopenten-1-ones is reported Treatment of dimethyl 2-oxopropylphosphonate (21) with excess triethyl orthoformate in the presence of ferric chloride hexahydrate provides the enol ether 22, which upon allylic bromination wi