A microwave induced reaction of dicyclopentadiene (1) was used to rapidly and conveniently
generate cyclopentadiene (2) which is stabilized in a polar solvent for subsequent use. In this
case 2 was used for Diels-Alder reactions at ambient temperature. A 3 min microwave induced reaction
of 1 in acetone gave a solution of 2, followed by a room temperature reaction with a limited
amount of a highly active dienophile, maleic anhydride (3), which afforded pure cis-endo-5-
norbornene-2,3-dicarboxilic anhydride (4). Simultaneous reactions were achieved in 0.5 min at 200°C
but some of the exo-isomer 5 also resulted. Several maleimides also demonstrated the convenient utility
of these microwave methods for reactions of 2 for valuable industrial compounds. This method now precludes the previous
arduous thermal cracking of 1 along with the simultaneous fractional distillation of 2.
Keywords: 1H NMR, acetone, biotage Initiator +, cis-endo-5-norbornene-2, 3-dicarboxylic anhydride, cis-exo-5-norbornene-
2, 3-dicarboxylic anhydride, cyclopentadiene, dicyclopentadiene, Diels-Alder, maleic anhydride, maleimide, microwave, Nmethylmaleimide,
N-phenylmaleimide, reaction severity, solvent stabilization.
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