Classical Example of Total Kinetic and Thermodynamic Control: The Diels–Alder Reaction between DMAD and Bis-furyl Dienes

A rare example of
chemospecificity in the tandem Diels–Alder
reaction of activated alkynes and bis-dienes has been revealed. The
reaction between bis-furyl dienes and DMAD occurs at 25–80
°C and leads to kinetically controlled “pincer”
adducts, 4a,8a-disubstituted 1,4:5,8-diepoxynaphthalenes. On the contrary,
only thermodynamically controlled “domino” adducts (2,3-disubstituted
1,4:5,8-diepoxynaphthalenes) are formed in the same reaction at 140
°C. The “pincer” adducts can be transformed to
the “domino” adducts at heating. The rate constants
for reactions of both types were calculated using dynamic 1H NMR spectroscopy.