Wittig olefination of 3,5-dimethoxy-4-methylbenzaldehyde (I) with butylidene triphenylphosphorane produced a Z/E mixture of olefins (II), which was hydrogenated over Pd/C to afford the n-pentyl derivative (III). Cleavage of the methyl ethers of (III) using iodotrimethylsilane provided diol (IV). Introduction of the aldehyde group in (IV) was achieved by Gattermann formylation with zinc cyanide and HCl. The target coumarin (VI) was prepared by Pechmann condensation of hydroxy aldehyde (V) with dibenzyl malonate. Glycosylation of (VI) with the noviose intermediate (VII) under Mitsunobu conditions produced the alpha-glycoside (VIII) as the major isomer. The free carboxylic acid was then obtained by catalytic hydrogenolysis of the benzyl ester (VIII).