Reissert Compounds as Precursors to Novel Phthalides

Heating of the Reissert compound 1 with sodium hydroxide in aqueous methanol gives the phthalideisoquinoline 2 in 58% yield. 

Condensation of 2-pyrone with dimethyl acetylenedicarboxylate and diethylacetylene proceeds in the expected manner. There is, however, no reaction between di-t-butylacetylene and 2-pyrone, even after solutions of the reactants in bromobenzene have been heated in a sealed tube at 210°C for 5 days. Instead, frans-cinnamic acid is obtained in low yield. 

A Failed Thorpe-Dieckmann Cyclisation Obvious Reactions are not Always Well Behaved. 

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