A Model System for the Synthesis of Complanadine Alkaloids by “Diverted Kondrat’eva” Oxazole–Olefin Cycloaddition

A synthetic approach
to complanadine alkaloids is described which
employs a Kondrat’eva reaction to construct the pyridine rings.
The viability of this approach is demonstrated by its application
to a model substrate accessed from unfunctionalized decalin. The key
transformation affords the desired tetracyclic architecture with unprecedented
incorporation of substituents on the pyridine ring, implicating the
oxazole α-hydroxy group as an active participant in the cycloadduct
fragmentation process.