Synthesis of 3-Demethoxyerythratidinone via Formation of a Dibenzazonine Alkaloid

Abstract

3-Demethoxyerythratidinone (1) was synthesized via the dibenzazonine base (7), which was prepared by irradiation of the phenolic compound (5) in an alkaline solution, followed by reduction of the resulting photocyclization product (6) with diborane. We investigated various oxidation reactions of 7 to yield the corresponding dienone (11). It was found that the use of active lead oxide and potassium ferricyanide as oxidants gave the dienone (11) in 65 and 60% yields, respectively. Finally, the dienone (11) was converted to 1 by hydrogenation.