Novel Two-Step Synthesis of Homobarrelenones, Bicyclonona-3,6,8-trien-2-ones, from Tropones and 2,3-Bis(methoxycarbonyl)-7-oxabicyclohepta-diene by High-Pressure Cycloaddition-Thermal Cyclorevision Procedure

Article abstract of DOI:10.1246/cl.1987.1557

The Diels-Alder adduct of tropone with 2,3-bis(methoxycarbonyl)-7-oxabicyclo<2.2.1>hepta-2,5-diene formed homobarrelenone by heating at ca. 130 deg C.Similarly prepared were 1-hydroxy-, 3-methoxy-, 1-chloro-, and 3-chlorohomobarrelenones.High-pressure cycloaddition improved the yields of the Diels-Alder adducts.