| Spirolucidine is a complex alkaloid isolated from the club moss Lycopodium lucidulum. A three fragment convergent plan for the title compound was envisioned, with each fragment being derived from a chiral N-acyl-2,3-dihydro-4-pyridone. The synthesis of the bicyclic enecarbamate referred to as zone C was investigated. The first effort centered on a tandem intramolecular Diels-Alder reaction/retro Mannich ring opening reaction to set the key stereogenic centers within zone C. A second strategy aimed to ring open the tricyclic adduct which arises from the Diels-Alder reaction through an E1cB mechanism. Finally, a third attempt was made to utilize chirality transfer as a means to implement the necessary stereochemical elements of the bicyclic scaffold.; The convergent union of the key fragments of spirolucidine was modeled on a simple substrate. The directed lithiation of N-Boc-dihydropyridines was utilized to prepare model 2,5,6-trisubstituted dihydropyridones of a general type needed for the completion of the spirolucidine synthesis. |
