A New Method for the Preparation of Bis(alkylamino)maleonitriles from Aliphatic Isocyanides with TMSCN and Bi(OTf)3

Abstract

Bis(alkylamino)maleonitriles are starting materials for the synthesis of a number of important intermediates, including porphyrazines that serve as dyes, pigments, and models of biologically active substances; hence, the development of improved methods for their preparation is important. Herein, we report a facile new method for the preparation of bis(alkylamino)maleonitriles from isocyanides. Treatment of tert-alkyl isocyanides with trimethylsilyl cyanide (TMSCN) and trimethylsilyl triflate (TMSOTf) in the presence of bismuth(III) triflate [Bi(OTf)3] afforded the corresponding bis(alkylamino)maleonitriles in moderate yields. tert-Alkyl isocyanides bearing a variety of functional groups, including halide, ether, ester, imide, amide, and carbamate, are tolerated under the developed reaction conditions. To the best of our knowledge, this is the first report of a synthetic method for the preparation of bis(alkylamino)maleonitriles in a single step from tertiary alkyl isocyanides.