Diterpenes transannular processes

BIOSYNTHESIS OF DITERPENES BASED ON CATIONIC CYCLIZATIONS, 1,2-SHIFTS, AND TRANSANNULAR PROCESSES 281... [Pg.281]

Our laboratory has also taken advantage of multiple insertion processes to access the scopadulan diterpenes (Scheme 6-24) [52]. An early example was the economical conversion of aryl iodide 136 to tetracycle 137, an intermediate which was subsequently converted to ( )-scopadulcic acid B (138). In this conversion, migratory insertion of the neighboring exocyclic alkene provided a tricyclic intermediate having no /5-hydrogens, which subsequently underwent a transannular 5-exo Heck reaction with the trisubstituted... [Pg.137]

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