A two-stage synthesis of 8,10a-epoxypyrido[2,1-a]isoindoles: Stereochemistry of the [4+2] cycloaddition of maleic anhydride with 2,6-difurylpiperidin-4-ones

A new straightforward synthesis of 8,10a-epoxypyrido[2,1-a]isoindoles and their 7-carboxylic acids from 2,6-difurylsubstituted piperidin-4-ones and maleic anhydride or acryloyl chloride via the intramolecular Diels-Alder reaction has been demonstrated. It has been shown that a one-stage synthesis of the title compounds can be performed under mild conditions and with high levels of regio-and stereoselectivity from easily accessible 2-furylpiperidines. © Georg Thieme Verlag Stuttgart - New York.