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[摘要]：Tetronic acid esters and amides, which are readily available from the corresponding tetronic acids, serve as useful starting materials in an intra-or intermolecular [2+2]-photocycloaddition reaction. Typical reaction conditions are irradiation at lambda = 254 nm in diethyl ether or an alcohol as the solvent. The bi-, tri- or tetracyclic products so obtained can be further utilized by ring opening either of the lactone or the cyclobutane ring. Lactone ring opening led to the use of a tetramide photocycloaddition product as a conformationally restricted beta-proline analogue and to an application of a tetronate photocycloaddition product in the total synthesis of punctaporonin C. |
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