Enantioselective total syntheses of the antitumor alkaloids,(+)-narciclasine and (+)- pancratistatin, are reported. These syntheses feature a stereo-and regiocontrolled aryl enamide photocyclization to construct a common, advanced intermediate possessing a trans- fused BC substructure. Differential functional group interchange in the C-ring of this phenanthridone core structure allows for the production of the two target natural products ...
