Abstract As an active diene (more active than furan itself), 3, 4-dimethoxyfuran (1) affords with many dienophiles the respective cycloadducts in a high yield [2]. It has recently been found that under thermal conditions 1 easily reacts with maleic anhydride and its monomethyl derivative, but not with dimethylmaleic anhydride (2)[3]. This is probably due to steric hindrance resulting from the location of two methyl groups on the double bond of the ...
![5,6-dimethoxy-2endo,3endo-dimethyl-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride Structure](https://image.chemsrc.com/caspic/006/82616-93-1.png)
