Furo[3,4-b]benzodioxin cycloadditions. A one-pot synthesis of
C. Bozzo, N. Mur, P. Constans, and M. D. Pujol. Furo[3,4-b]benzodioxin
cycloadditions. A one-pot synthesis of functionalized bis-adducts. European
Journal of Organic Chemistry, 2009, 2174-2178 (2009).
Furo[3,4-b]benzodioxin 1 was found to undergo a doubleDiels-Alder
reaction with several dienophiles. The diene reacts directly with the suitable
dienophile to give the mono-adduct intermediate that unexpectedly leads to a second
cycloaddition at the internal, electron-rich, oxabicyclic C4a-C10a double bond. The
resulting bis-adducts were formed under relatively mild conditions with dienophiles
ranging from maleic anhydride and dimethyl acetylenedicarboxylate to the extremely
reactive arynes. With this methodology of two uninterrupted sequential cycloaddition
reactions, interesting formation of stable bis-adducts was observed. The dienophile
behavior of 1,4-benzodioxin is described for the first time in this work.
Cycloaddition, fused-ring systems, polycycles, dienophiles, oxygen heterocycles.
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