A 4-substituted η-lactone is produced by introducing a 1-alkynyl group into the 1-carbon atom of 2,3-O-isopropylidene-D-ribofuranose, cleaving the resulting compound at the diol part to give a lactol, oxidizing it into a lactone, hydrolyzing the ketal group of the lactone, reducing the hydrolyzate, removing the 2- and 3-hydroxyl groups, and hydrogenating the double bond between the 2- and 3-carbon atoms of the product.