S. Chattopadhyay et al., DIELS-ALDER REACTION OF DEACTIVATED DIENES WITH ELECTRON-POOR DIENOPHILES, Indian journal of chemistry. Sect. B: organic chemistry, including medical chemistry, 35(6), 1996, pp. 605-607
1,3-Butadiene derivatives carrying phenyl/methyl and carboxyl/ester gr
oups react with N-arylmaleimides and maleic anhydride in refluxing xyl
ene to form the Diels-Alder adducts in good yields.