Ophiobolane synthesis

Valuable applications of this principle have been described by Paquette for the synthesis of topologically spheric molecules. Coates used this reductive fragmentation for the synthesis of bicy-clo[6.3.0]undecenecarboxylates, compounds which bear a structural resemblance to the a-b rings of the fusicoccin and ophiobolane natural products. Reduction of the unsaturated keto ester (164) affords an isomeric mixture of esters, the equilibration of which effects conversion to the single ester (165 Scheme 56). 

The intramolecular (4n + 4ti) photoaddition of furan-pyran-2-one bichromo-phores [e.g. (38) to give (39)] is potentially useful as an approach towards the fusicoccane/ophiobolane skeleton (Chase et al.), and the formation of (40) from the irradiation of (41) constitutes the first example of a (47t + 4ji) photocycloaddition of an enone to the benzene ring (Kishikawa et al.). Wender et al. continue to report elegant new applications of the intramolecular meta photocycloaddition of 5-phenylpent-l-ene derivatives and have described the synthesis of cis,cis,cis, traMi-[5,5,5,5]-fenestrane (42) using the photoreaction of (43) as a key step. Park... 

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