Expeditious Multicomponent Synthesis of Xanthone Dimers

Abstract

Xanthones are a type of compound widely found in many natural products from plants, fungi, and lichens and are considered privileged structures. Frequently, xanthones occur in nature as dimers, which often exhibit singular and potent biological effects. Although diverse methods for the synthesis of monomeric xanthones are known, dimeric xanthones remain synthetically challenging targets. Reported syntheses of dimeric xanthones are very scarce, and invariably involve a large number of synthetic steps. We have recently developed a multicomponent synthesis of xanthones starting from 3-carbonylchromones, isocyanides, and dienophiles. Here we report a similar one-pot tandem procedure, involving a [4+1]-[4+2] cycloaddition, that readily affords dimeric xanthones and dihydroxanthones, which are structurally similar to bioactive ergochromes.

An Update on the Anticancer Activity of Xanthone Derivatives: A Review

“…The coupling reaction between methyl salicylate and diaryliodine triflate salt yielded xanthone derivative in 72% yield, however, the reaction took 12 h to reach the equilibrium state [75]. In 2019, multicomponent synthesis of xanthone dimer was reported from isocyanide, dienophile, and 3-carbonylchromone in 79% yield through [4+2] cycloaddition [87]. Recently, in 2021, one-pot synthesis of xanthone was reported through carbonylative Suzuki coupling reaction by Loureiro et al This synthetic route utilized three reagents: ortho-iodophenol, organoboron, and carbon monoxide, with Pincer palladium as complex as the catalyst material.…”

“…72% yield [75] ~100% yield [88] 79% yield [87] The functional groups' interconversion of xanthone derivative is shown in Figure 9. In general, methylation, formylation, nitration, and halogenation reactions of the xanthone aromatic rings can be directly performed.…”