| (+/-)-Decursivine was isolated in 2002 and possessed a substituted indole with appropriate functionality for synthesis via a modified Plieninger indole synthesis. The synthesis began with a Diels-Alder reaction of a quinone monoimine with butadiene. The resultant dihydronaphthalene was then carried forward to an indole with the appropriate functionality to synthesize decursivine. The indole so produced could be utilized in a key boron aldol reaction with piperonal. Following installation of the tryptamine unit via acid catalyzed Michael addition, simple oxidation state and protecting group manipulations completed the total synthesis of decursivine. In all, the total synthesis of (+/-)-decursivine was completed in 21 steps and 3% overall yield, very good for a synthesis of this length.;More recently, a new methodology capable of producing 2,5-cis -pyrrolidines has been applied to the synthesis of (--)-allosecurinine. Synthesis of the required pyrrolidine was performed utilizing an intramolecular oxime-ether cyclization and a hydrogenolysis of the resultant N,O-bond. Dealkoxycarbonylation and dehydration of this pyrrolidine yielded a substrate amenable to oxygenation utilizing Davis' oxaziridine. Following several synthetic operations a substrate was produced which could be transformed via RCM and a Horner-Emmons reaction into the core of allosecurinine. Simple deprotection and ring closure of the piperidine completed the total synthesis of (--)-allosecurinine in 15 linear steps and 5% overall yield.;Key words. Natural Product Synthesis, Decursivine, Diels-Alder, Boron Aldol, Plieninger Indole Synthesis, Allosecurinine, Cyclopropanes, Oxime Ethers, Pyrrolidine, Cycloaddition. |
