Citation: P. Wipf et Ws. Weiner, Enantioselective synthesis and photoracemization studies of (+)-2-cyclopropyl-7,8-dimethoxy-2H-chromene-5-carboxylic acid methyl ester, an advanced intermediate of a dihydrofolate reductase inhibitor, J ORG CHEM, 64(14), 1999, pp. 5321-5324