SYNTHESIS OF AZULENONE SKELETON BY REACTION OF 2-PHENYL-2-ACYLKETENES[RCO(PH)C=C=O] WITH ALKYNYL ETHERS - MECHANISTIC ASPECTS AND FURTHER TRANSFORMATIONS

A method is described for a mild and efficient synthesis of azulenone skeletons sis the addition reactions of 2-phenyl-2-acylketenes with 1- alkynyl ethers. A mechanism is presented to account for both azulenone formation as well as the solvent and substrate dependency of a compet itive pyrone formation. The azulenone rings have been subsequently tra nsformed into both substituted azulenes or hydroazulenes by derivatiza tion and/or decarboxylation of an angular carboxyl substituent or by h ydrogenation.