Synthesis and Reactions of Highly Electrophilic Imines Containing the N-Cyano Group

Article abstract of DOI:10.1021/jo00293a019

Toluene solutions of tricyanomethanimine, 1, and methyl 3-aza-2,3-dicyanoacrylate, 2, were synthesized by thermal decomposition of, respectively, 2,2-diazido-1,1-dicyanoethylene and methyl 3,3-diazido-2-cyanoacrylate.Diethyl (cyanoimino)malonate, 3, was obtained from the reaction of diethyl ketomalonate with bis(trimethylsilyl)carbodiimide.None of these electrophilic imines could be isolated, because oligomerization occurred in every case.Dilute solutions of 1 and 2 in toluene were stable for several days, so the imines were characterized in solution.Cycloadditionreactions with 2,3-dimethylbutadiene and cyclopentadiene lead to the expected Diels-Alder adducts.With p-methoxystyrene, spontaneous copolymerizations occurred with both 1 and 2.These imines were somewhat less electrophilic than tetracyanoethylene; they behave similarly in cycloaddition reactions, but in contrast they are also able to polymerize.