1,3-Butadiene → 5,6-Dimethyl-3a,4,7,7a-tetrahydro-2-benzofuran-1,3-dione

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Reaction Steps

As shown above in 2.1.2 to 2.4.2 maleic acid anhydride is reacted with a suitable conjugated diene compound to give the wanted Diels-Alder reaction product. For example maleic acid anhydride reacted with butadiene in benzene or dioxane at ambient temperature is quantatively transferred to cis-1,2,3,6-tetrahydrophthalic acid anhydride (K. Alder et al, Liebigs Annalen der Chemie, 460, 98 (1928) and 514, 1 (1934)). In the reaction of maleic acid anhydride with 2,3-dimethyl-1,3-dibutadiene in nitromethane and addition of 5 mol % of a rhuthenium catalyst on a hydroxyl apatite support, 5,6-dimethyl-3a,4,7,7a-tetrahydro-isobenzofurane-1,3-dione is formed (K. Mori et al. JACS 125, 11460 (2003)). 4,10-dioxatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione is formed by reacting maleic acid anhydride with furane in diethylether. First the kinetically faster endo-product is formed which during 8 h at ambient temperature completely rearranges to the thermodynamically stable exo-product (R. B. Woodward and H. Baer, JACS 70 1161 (1948)). Maleic acid anhydride and 1,3-cyclohexadiene in benzene with heating at ambient temperature quantitatively react to 4-oxatricyclo[5.2.2.02,6]undec-8-ene-3,5-dione.

Provenance & Evidence