Pyranopyrone

In preceding sections the thermal rearrangement of suitably substituted propynyl pyridyl ethers and propynyl pyrimidinyl ethers to furopyridines and furo[3,2-d]pyrimidines, respectively, has been described. By strict analogy with these reactions, heating propynyl kojate in vacuo at 160 °C gives a f uro[3,2-Z> Jpyrone with no trace of a pyranopyrone (equation... 

Money, Scott and coworicers utilized a similar strategy of protecting the labile polyketcxie as a pyrone ring. As shown in equation (150), pyranopyrone (133) reacts with aqueous base to give orsellinic acid, presumably by way of the intermediate triketo diacid (134). 4 procedure was found to be quite general equation (151) shows a further application in the synthesis of pinosylvin, (135). ... 

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