1337916-83-2Relevant academic research and scientific papers
Synthesis of 6 H-dibenzo[ b, d ]pyran-6-ones using the inverse electron demand Diels-Alder reaction
Pottie, Ian R.,Nandaluru, Penchal Reddy,Benoit, Wendy L.,Miller, David O.,Dawe, Louise N.,Bodwell, Graham J.
experimental part, p. 9015 - 9030 (2011/12/03)
A set of coumarin-fused electron-deficient 1,3-dienes was synthesized, which differ in the nature of the electron-withdrawing group (EWG) at the terminus of the diene unit and (when EWG = CO2Me) the nature and position of substituents. These dienes reacted with the enamine derived from cyclopentanone and pyrrolidine to afford the corresponding cyclopenteno-fused 6H-dibenzo[b,d]pyran-6-ones, most likely via a domino inverse electron demand Diels-Alder (IEDDA)/elimination/transfer hydrogenation sequence. The parent diene (EWG = CO2Me, no substituents) was reacted with a range of electron-rich dienophiles (mostly enamines) to afford the corresponding 6H-dibenzo[b,d]pyran-6-ones or their nondehydrogenated precursors, which were aromatized upon treatment with a suitable oxidant. The enamines could either be synthesized prior to the reaction or generated in situ. The syntheses of 30 dibenzopyranones are reported.
