Intramolecular Alkene-Oxirane Cycloadditions. Synthesis and Structure of 5-Oxapentacyclo(7.3.0.0(3,7).0(4,12)0.(6,10))Dodecane-2,8-Dione

摘要

MCPBA promoted epoxidation of the C(9)-C(10) double bond in endo-tri cyclo-(6.2.1.o(2,7))undeca-4, 9-diene-3, 6-dione (4) followed by intramolecular (2 + 2) photocyclization of the resulting exo epoxide (5) afforded the title compound, 1, in 16% overall yield. The structure of symmetrically hydrated 1 (i.e., la) was determined by single crystal x-ray crystallographic methods. Proton and carbon-13 NMR spectral assignments are given for epoxide 5. Keywords: Intramolecular Alkene oxirane Cycloaddition, Photocycloaddition, X-ray crystal structure, Reprints. (js)