Epiprecapnelladiene synthesis

The intramolecular variant of the de Mayo reaction has been applied in the synthesis of -bulnesene (21), epiprecapnelladiene (22), and of the zizaane carbon skeleton (23). Coates et have described a variant of this general strategy for ring synthesis whereby but-2-enolides are used as one of the TT-components in the photocycloaddition. 

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