Ene Reactivity of an Fe═NR Bond Enables the Catalytic α-Deuteration of Nitriles and Alkynes.

Herein, we report the reactions of an Fe(II) imido complex [PhB(BuIm)Fe═NDipp] () with internal alkynes and isobutyronitrile, affording the Fe amido allenyl complexes [PhB(BuIm)Fe(NHDipp)((R)C═C═C(R)(H))] (R = Et or Pr; R = Me or Et, ) and the Fe amido keteniminate complex [PhB(BuIm)Fe(NHDipp)(N═C═CMe)K(THF)] (), respectively. These transformations represent the previously unknown ene-like reactivity of a metal-ligand multiple bond. Stoichiometric reactions of and with DippNH lead to the regeneration of 3-hexyne and isobutyronitrile, respectively, with concomitant formation of the bis(anilido) complex [PhB(BuIm)Fe(NHDipp)] (). These results provide the platform for as an efficient catalyst for the selective α-deuteration of nitriles and alkynes by RND. These results demonstrate a new reaction mode for metal imido complexes and suggest new avenues for using the imido ligand in catalysis.