A novel synthesis of coumarins based on the ortho-directed metalation of methoxymethyl phenolic ethers with alkyllithium reagents is described. The method entails reaction of the ortho-lithiated intermediates with dimethylformamide to yield the corresponding ortho- aldehydes. Reaction of the latter with lithio-N, N-dimethylacetamide affords the addition products which on heating in refluxing acetic acid undergo smooth conversion directly to ...
