A NOVEL-APPROACH TO THE SYNTHESIS OF MORPHINE ALKALOIDS - THE SYNTHESIS OF (D,L)-THEBAINONE-A

A nonconventional approach to the preparation of morphinans has been applied to the total synthesis of thebainone-A and beta-thebainone-A. Noteworthy features of this synthesis are the regiospecificity of the Diels-Alder reaction to form 9 and of the enolization-hydroxylation of 11, the unusual aromatization of 14 as well as the selectivity of the intramolecular Michael addition of the amine to form 41. This route offers access to several alkaloid skeleta which are related to morphine as well as demonstrating a new approach to the synthesis of aromatic molecules.