Total syntheses of pyrroloazocine indole alkaloids: challenges and reaction discovery

Abstract

Total syntheses of pyrroloazocine indole alkaloids (lapidilectines, grandilodines, lundurines and tenuisines) are discussed in terms of existing retrosynthetic solutions and novel reaction discoveries.

Buchwald‐Type Ligands on Gold(I) Catalysis

“…Recently, our group has demonstrated the potential of the gold-catalyzed intramolecular hydroarylation of indoles to construct the pyrroloazocine indole core in 17 [61] which was later applied in the total syntheses of Kopsia alkaloids [62] (À )lundurines A-C [63] and seven members of the lapidilectine/ grandilodine family. [64] Analogously, gold(I) complexes supported by Buchwaldtype phosphines are able to modulate the reactivity of 1,6enyne bearing propargylic alcohols, ethers or silyl ethers.…”

Cu‐Mediated Synthesis of Indolines and Dihydroisoquinolinones through Arylperfluoroalkylation of Unactivated Alkenes

“…Indoles, including indolines and oxindoles, are valuable structural motifs that widely existed in bioactive natural products, and clinical drugs . Developing convenient and efficient methods for the construction of indole skeleton has long been received significant attention in industrial and academic society.…”

Gold(I)‐Catalysis for the Synthesis of Terpenoids: From Intramolecular Cascades to Intermolecular Cycloadditions

“…In this account, we review our efforts to apply gold(I) catalysis for the synthesis of terpenoid‐type natural products, from cyclizations of dien‐ or polyenynes, to formal [4+2], [2+2+2] cycloadditions, to reactions proceeding by more complex cascades involving alkoxy propargyl migration. For consistency, the application of the arylalkyne/alkene [4+2] intramolecular cycloaddition in the context of linear acene synthesis is also discussed, whereas our work on gold‐catalyzed heteroarene‐alkyne cyclizations, in the context of alkaloid synthesis are not included ,. In the second section, two syntheses of natural products based on disatereoselective 1,5‐enyne cyclizations are presented.…”

“…For consistency, the application of the arylalkyne/alkene [4 + 2] intramolecular cycloaddition in the context of linear acene synthesis is also discussed, whereas our work on goldcatalyzed heteroarene-alkyne cyclizations [60,61] in the context of alkaloid synthesis are not included. [62,63] In the second section, two syntheses of natural products based on disatereoselective 1,5-enyne cyclizations are presented. Finally, our long-term goal at developing an enantioselective gold(I)catalyzed intermolecular cycloaddition of alkynes with alkenes is also discussed.…”