Palladium(II)-Catalyzed Reaction of Lawsones and Propargyl Carbonates: Construction of 2,3-Furanonaphthoquinones and Evaluation as Potential Indoleamine 2,3-Dioxygenase Inhibitors.

An efficient reaction utilizing propargyl carbonates through Claisen rearrangement to synthesize furanonaphthoquinones is described. The remarkable transformation exhibits excellent functional group tolerance, affording the target furanonaphthoquinones in moderate to good yields (41-85%) under mild reaction conditions. Scaled-up preparation of the model product can make this reaction a method of choice for synthesis of furanonaphthoquinone derivatives. The resulting furanonaphthoquinones were evaluated as potential indoleamine 2,3-dioxygenase inhibitors in vitro.