1,2-cyclobutanedicarboxylic acid, diethyl ester, (1R,2R)- InChI=1/C10H16O4/c1-3-13-9(11)7-5-6-8(7)10(12)14-4-2/h7-8H,3-6H2,1-2H3/t7-,8-/m1/s diethyl (1R,2R)-cyclobutane-1,2-dicarboxylate trans diethyl-1,2-cyclobutanedicarboxylate