An overview: total synthesis of arborisidine, and arbornamine.

Arborisidine and Arbornamine are two monoterpenoid indole alkaloids that were isolated from the Malayan Kopsia arborea plant. This review provides valuable information about the total and formal syntheses of these alkaloids. The synthesis strategies discussed in this review, such as Pictet-Spengler cyclization, chemo- and stereoselective oxidative cyclization, Michael/Mannich cascade process, and intramolecular N-alkylation, can be useful for developing new methods to synthesize these and other similar compounds.

Divergent Synthesis of Skeletally Distinct Arboridinine and Arborisidine.

A divergent synthesis of skeletally distinct arboridinine and arborisidine was achieved. The central divergent strategy was inspired by the divergent biosynthetic cyclization mode of arboridinine and arborisidine and their hidden topological connection. The branch point was reached through a Michael and Mannich cascade process. A site-selective intramolecular Mannich reaction was developed to construct the tetracyclic core of arboridinine, while a site-selective intramolecular α-amination of ketone was used to access the tetracyclic core of arborisidine. A strategic Peterson olefination through intramolecular nucleophile delivery was able to set up the exocyclic olefin of arboridinine.

Total Synthesis of (-)-Arborisidine.

An asymmetric total synthesis of cage-like indole alkaloid arborisidine is presented. The new synthetic strategy features a catalytic parallel kinetic resolution based on ambident nucleophilicity (C3/N) of indole to set the absolute configurations of the two quaternary chiral centers, and a 5-exo-trig radical cyclization to form the bridged nitrogen-containing five-membered ring.