Dimethylfumarate Diels-Alder reactions

Various o-quinodimethanes, generated in situ from o-alkenylbenzyltributyl-stannane precursors, have been used to synthesize functionalized polycycles by Diels Alder reaction with maleic anhydride, methylacrylate, dimethylfumarate and N-phenyl maleimide in the presence of electrophiles [37] (Scheme 2.16). 

By measuring the rate constant of the cycloaddition between cyclopentadiene and dimethylfumarate, Schneider [28] demonstrated the importance of solvophobic effects, quantified by solvophobic power (Sp) values [29], which originate from the standard free energy of transfer of alkanes from the gas phase to a given solvent. Such a sensitivity of Diels-Alder reactions to solvent hydrophobicity depends, however, on the nature of the reagents [ 30] and is more pronounced for the reactions with a more negative activation volume [31]. Evidence for presence of en-... 

Chung has taken advantage of the difference in alkene reactivities to perform a one-pot PKR/Diels-Alder reaction. The reaction combined a 2 1 3 mixture of norbomene, 1-ethynylcyclohexene and dimethylfumarate, respectively. A 90% yield of the pentacyclic products 54 and 55 were formed in a 1.1 1 ratio. 

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