Cyclopentadienone epoxides synthesis

A facile synthesis of cyclopentadienone epoxides via thermal rDA cycloreversion of a tricyclodece-none epoxide and its acetal derivatives has been applied to the preparation of cyclopentanoid antibiotics. - This procedure has been used in an efficient synthesis of terrein, a mould metabolite from Aspergillus terreus, by rDA synthesis of cyclopentadiene epoxide intermediate (57). FVP conditions for these reactions typically involve temperatures of 420-600 C. Furan-derived DA adducts have also been used to generate cyclopentadienone epoxides. The thermal rDA reaction of the furan-derived DA adduct (58) proceeds at temperatures as low as 330 °C with complete cycloreversion and generation of epoxide (59) in nearly quantitative yield (equation 32). Subsequent elaboration led to epipentenomycin derivatives such as (60). 

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