A method for the synthesis of 1-methylcarbapentofuranose derivatives was developed, where 1,2-cis- and 1,2-trans-4-hydroxymethyl-1-methylcyclopentanediols were obtained from intramolecular opening of a 4-epoxy-4-methyl-gamma-lactone. An intramolecular aldol reaction of 4-methyl-4-(2-oxoethyl)-gamma-lactone derivatives yielded 1,3-cis- and 1,3-trans-4-hydroxymethyl-1-methylcyclopentanediols.