Synthetic Exploitation of the Ring-Opening of 3,4-Dinitrothiophene. Part 3. Access to 1,4-Diaryl- and 1,4-Dialkyl-2-nitrobutanes

1,4-Diaryl- and 1,4-dialkyl-2,3-dinitro-1.3-butadienes 1a-i are smoothly converted, in MeOH or MeOH-dioxane, to the corresponding 1,4-disubstituted 2-nitrobutanes 4a-i by borohydride supported on ion-exchange resins.