Condensation with t-butyl acrylate results in cyclization to t-butyl 7-methoxychromene-3-carboxylate: J. Med. Chem., 36, 3580 (1993). With (Ethoxycarbonyl-methyl-ene)-triphenyl-phosphorane, in N,N-diethylaniline cyclization to 7-methoxycoumarin occurs: Heterocycles, 39, 613 (1994).