Journal or Book Title
The Journal of Organic Chemistry
A general procedure is described where an aryllithium, generated by metalation of a protected phenol with n-butyllithium, adds in a conjugate manner to diethyl ethoxymethylenemalonate to give after acid hydrolysis an oxygenated 3-carbethoxycoumarin. By this procedure the ethyl vinyl ethers 9, 11, 13, and 15 are converted into the corresponding coumarins 10, 12, 14, and 16 in a single reaction vessel in good yield.
American Chemical Society
Kraus, George A. and Pezzanite, John O., "Michael additions in anhydrous media. A novel synthesis of oxygenated coumarins" (1979). Chemistry Publications. 801.