Conjugate addition of nitroalkanes to N-substituted maleimides. Synthesis of 3-alkylsuccinimides and pyrrolidines

3-Alkylidenesuccinimides obtained by conjugate addition of nitroalkanes to N-substituted maleimides can be reduced to the corresponding 3-alkyl derivatives by catalytic hydrogenation. 3-Alkylsuccinimides can be further reduced using BH3·Me2S complex to afford 3-alkylpyrrolidines in good yield.