Synthesis of croconic and hydrocroconic acids from di-t-butoxyethyne. Electrochemical demetallation of a cyclopentadienyl organocobalt complex

Abstract

The electrochemical demetallation of (η-tetra-t-butoxycyclopentadienone)(ηcyclopentadieny)cobalt, readily available from di-t-butoxyethyne leads to tetra-t-butoxyclopentadienone which can be converted into hydrocroconic acid by trifluoroacetic acid hydrolysis and then croconic acid by oxidation in basic medium.