A convenient and selective one-pot method for the synthesis of monosubstituted secondary alkyl malononitriles

We have found that α,α-dicyanoalkenes can be efficiently and selectively reduced to α,α-dicyanoalkanes (malononitriles) with NaBH 4 in 95% EtOH at 0 °C. In addition, we have determined that the condensation of malononitrile with ketones using absorption alumina as a catalyst can be followed directly, in one pot, by reduction with NaBH 4 in 95% EtOH at 0 °C to provide the monosubstituted secondary alkyl malononitriles in good to excellent yields (42-94%). This procedure provides a convenient alternative to direct alkylation of malononitrile or reduction of α,α-dicyanoalkene intermediates.