The reaction of tetracyanoethylene oxide with methyl erucate (methyl cis-13-docosenoate) and methyl bras sidate (methyl trans-13-docosenoate) gave 2,2,5,5-tetracyano-3-(11-carbomethoxyundecyl)-4-octyltetrahydrofurans (2 and 3) in good yields. In methanol containing 5% hydrogen chloride, both 2 and 3 undergo partial and selective methanolysis to give 2,5-dicyano-2,5-dicarbomethoxytetrahydrofuran derivatives (4 and 5). The newly formed carbomethoxy groups are trans to their adjacent alkyl groups. Both 2 and 3 also are partially and selectively hydrolyzed on the surface of silica gel to give 2,5-dicyano-2,5-dicarbamoyltetrahydrofuran derivatives (10 and 11) in good yields. The newly formed carbamoyl groups have a cis relationship to each other. © 1969, American Chemical Society. All rights reserved.