A Convenient and Selective One-Pot Method for the Synthesis of Monosubstituted Secondary Alkyl Malononitriles
作者:Robert Sammelson、Mark Allen
DOI:10.1055/s-2004-837290
日期:——
We have found that α,α-dicyanoalkenes can be efficiently and selectively reduced to α,α-dicyanoalkanes (malononitriles) with NaBH4 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 NaBH4 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.
我们发现,α,α-二氰基烯烃可以在0°C下,以95%乙醇中的NaBH4高效且选择性地还原为α,α-二氰基烷烃(丙二腈)。此外,我们还确定,使用吸附氧化铝作为催化剂,将丙二腈与酮缩合后,可以直接在同一反应器中,在0°C下使用95%乙醇中的NaBH4进行还原,从而以良好至极佳的产率(42-94%)得到单取代的次烷基丙二腈。这一方法提供了一种方便的替代方案,无需直接烷基化丙二腈或还原α,α-二氰基烯烃中间体。