Total Synthesis of Dictyodendrins B and E

Abstract

The concise synthesis of the novel telomerase inhibitors dictyodendrins B and E was completed in only 9 and 11 steps (longest linear sequence). The highly convergent strategy employed a palladium-catalyzed Larock indole synthesis and a palladium-mediated one-pot consecutive Buchwald-Hartwig amination/C-H activation reaction as key steps. The present synthesis exhibits respectable levels of atom-, redox-, and step-economy.

Simple indole alkaloids and those with a nonrearranged monoterpenoid unit

“…Palladium-catalyzed Larock indole annulation was used for the construction of 89, and the advanced intermediate 90 was assembled by Buchwald-Hartwig amination/C-H activation reaction (Scheme 22). 53 The total syntheses of ve amaryllidaceae alkaloids, lycoranines A (92) and B (93), 2-methoxypratosine (94), oxoassoanine (95), and anhydrolycorinone (96) Oxoassoanine (95) and anhydrolycorinone (96) were synthesized by intramolecular biaryl coupling involving t-BuOK-initiated single electron transfer to the C-Br bond (Scheme 24). 55 The halodecarboxylation of arenedicarxylic acid leading to a dihalogenated product was applied for the synthesis of kalbretorine (97).…”

Transition Metal‐Catalyzed CH Activation of Indoles

“…[171] Theg roup designed al ate step C À Ha ctivation step of the C-4 position of as ubstituted indole to approach an intermediate that through subsequent elaboration furnished the desired targets.…”

Synthesis of Natural Products and Pharmaceuticals via Catalytic CH Functionalization

“…In 2013, Jia and coworkers accomplished the total synthesis of clavicipitic acid (Scheme 16.5), which is the same natural product as shown in Section 16.2.1.3 [14]. In their synthetic strategy, regioselective C-H alkenylation at the C4 position of tryptophan derivative 23, with a directing group on the amino unit, was designed as the key step.…”

“…Furthermore, this intramolecular C-H coupling was utilized in the synthesis of the carbazole moiety of dictyodendrins B and E by Jia and coworkers, although a stoichiometric amount of palladium was required (Scheme 16.16b) [14].…”