Stilbene Photocyclization. Synthesis of Cepharanone B

The photocyclization of enamides of type 2 is investigated.Photochemical electrocyclization did not take plaoe due to an ineffectiveness of overlapping of the hexatriene system.nowever, radical induced cy~lization gave a satisfactory result.AS a continuation to our studies on the synthesis of aporphine alkaloids and related compounds, we recently became interested in the highly oxidized members of this alkaloid group, namely oxo- aporphines, 4.5-diaxoaporphines and aristolactamsl.We should now like to report on the synthetic Studies2 leading to the latter class of compounds.' .