A new anionic cyclization reaction: Condensation of benzoate esters with nitriles to give 3-amino-2-inden-1-ones

A new type of anionic cyclization has been discovered in which the condensation of alkyl benzoates with simple nitriles, induced by an excess of LDA, leads directly to substituted-3-amino-1-ones. The corresponding intermediate β-oxonitriles undergo cyclization to give, in most instances, superior yields of the same compounds. Acid hydrolysis of these indenones leads in high yield to the corresponding biologically active (anticoagulant) indandiones.