SYNTHETIC STUDIES ON INDOLE ALKALOIDS - A STEREOCONTROLLED ENTRY TO THE CUANZINE STRUCTURAL UNIT

An efficient synthesis of the cuanzine precursor 4d has been achieved beginning with 8-methoxy-dihydro-β-carboline 3b and utilizing as the key step the stereocontrolled alkylation of 16a (and/or 20a) followed by Hg(II)-induced heterocyclization. The structure and stereochemistry of 4d are thereby corroborated by chemical correlation with natural cuanzine 1a.