2,3-dimethylene-2,3-dihydro-, Diels-Alder reactions

The dioxin system (effectively a 1,2-ethenodioxy structure) is derivable from catechol and the Diels-Alder reaction shown between one such compound namely 2,3-dimethylene-2,3-dihydro-1,4-benzodioxin and methyl vinyl ketone at 70°C for 15 hours a reaction which has enabled a tricyclic compound in the series to be synthesised in 84% yield (ref. 103). 

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