Coumarin with methyl magnesium iodide

Coumarins, and isocoumarins, react with Grignard reagents, as do esters, and can give mixtures of products, resulting from ring opening of the initial carbonyl adduct the reaction of coumarin with methyl magnesium iodide illustrates this." ... 

Metljylcoumarone has been prepared by the cyclization of ethyl a-phenoxyacetoacetate followed by hydrolysis and decarboxylation of the resulting ethyl 3-methylcoumarilate,3 4 by debromination and rearrangement of 3,4-dibromo-4-methyl-coumarin to 3-methylcoumarilic acid followed by decarboxylation,4-6 by cyclization of phenoxyacetone with concentrated sulfuric acid,6 and by treatment of 3-coumaranone with methyl-magnesium iodide followed by dehydration of the resulting car-binol.7... 

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