Systematic reductive oligomerization of isocyanides with a vanadium() complex

Using a V( ii ) complex as a reducing reagent, we demonstrate controlled reduction of isocyanides, resulting in decyanation of alkyl isocyanides to form a V( iii ) cyanide complex or oligomerization of aryl isocyanides to form trimers and a tetramer. The pathways leading to the trimers involve a divanadium ynediamido intermediate, which further reacts with the third isocyanide molecule to selectively produce a tri(imino)deltate or an indolenine complex, by altering the temperature and stoichiometry. The vanadium( ii ) complex is shown to mediate reductive oligomerization of aryl isocaynides, leading to formation of a dimer, trimers, and tetramers. The analogous reaction with alkyl isocyanides results in C-NC bond cleavage.