Total Synthesis of (−)-Goniomitine

The total synthesis of (−)-goniomitine has been accomplished in 11 steps starting from commercially available diethyl l-malate. The synthesis features a chiral pool approach to prepare the chiral C-9 unit containing a quaternary carbon center, an Ir-catalyzed C–H borylation to synthesize the 2-indoleboronic acid pinacol ester, and a Suzuki reaction to couple together the two key intermediates. Notably, the high degree of convergence of this strategy makes it particularly amenable to the total synthesis of other aspidosperma family natural products

Formal Synthesis of (+)-Kopsihainanine A and Synthetic Study toward (+)-Limaspermidine

The formal synthesis of (+)-kopsihainanine A has been achieved via stereoselective reduction of tetracyclic iminium ion intermediates (<b>24</b>). However, attempts to synthesize (+)-limaspermidine by reduction of the same tetracyclic iminium ion intermediates have failed. The synthesis features a Suzuki cross-coupling reaction, a cyclization reaction mediated by trifluoromethanesulfonic anhydride, and stereoselective reduction of an iminium ion

Direct Olefination at the C‑4 Position of Tryptophan via C–H Activation: Application to Biomimetic Synthesis of Clavicipitic Acid

The first Pd-catalyzed method for direct olefination at the C4 position of tryptophan derivatives has been developed via C–H activation to prepare 4-substituted tryptophans, which could be used for the synthesis of many hemiterpenoid indole alkaloids. This reaction proceeds under mild reaction conditions and with exceptional tolerance to a variety of functional groups. Furthermore, the efficiency of this method is demonstrated by the rapid and biomimetic synthesis of clavicipitic acid

Stereoselective Synthesis of the C₅–C₁₈ Fragment of Halichomycin

An efficient and convergent synthesis of the C₅–C₁₈ fragment of halichomycin is reported. Butanolide fragment <b>6</b> was readily prepared stereoselectively from (<i>R</i>)-Roche ester through catalyst control; dienylic bromide domain <b>7</b> was synthesized from (<i>S</i>)-serine by substrate control. C₅–C₁₈ fragment <b>2</b> was rapidly assembled through a stereoselective alkylation of the butanolide with the dienylic bromide, followed by functional group transformations

Total Synthesis of Dictyodendrins B and E

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

Total Synthesis of Dictyodendrins B and E

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

Total Synthesis of Dictyodendrins B and E

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

Total Synthesis of (+)-Lysergic Acid

We report the enantioselective total synthesis of (+)-lysergic acid using two different strategies, which featured three metal-catalyzed reactions for the construction of the BCD three rings, involving Pd-catalyzed indole synthesis for the construction of the B ring, a ring-closing metathesis reaction for the formation of the D ring, and an intramolecular Heck reaction to forge the C ring. In synthetic strategy I, the synthesis was achieved in 20 steps following the ring construction sequence of BDC. In synthetic strategy II, the synthetic route was shortened to only 12 steps by following the ring construction sequence of DBC and using a 4-chlorotryptophan derivative for the intramolecular Heck reaction. Moreover, we also discussed an unsuccessful synthetic strategy

Regioselective Direct C‑4 Functionalization of Indole: Total Syntheses of (−)-Agroclavine and (−)-Elymoclavine

An efficient rhodium-catalyzed method for direct C–H functionalization at the C4 position of unprotected indoles has been developed. The utility of this method is demonstrated by the concise total syntheses of agroclavine and elymoclavine in a divergent manner. These syntheses feature a Pd-catalyzed asymmetric allylic alkylation reaction to assemble the triyclic indole moiety, and a ring-closing metathesis reaction to form the D ring