Cationic nickel complexes of the form L2Ni(CH 3)(RN=C(H)R)+ (L2 = bidentate nitrogen donor) have been probed for their ability to mediate olefin and imine migratory insertion reactions. While these complexes do not undergo alkene insertion into the nickel-methyl bond, the use of olefin-tethered imines CH2= CH(CH2)nN=C(R)aryl (n = 1-3; R = H, methyl, phenyl) and the addition of CO initiates competitive olefin and imine insertion into the in situ generated nickel-acyl complex. The insertion selectivity shows clear steric and electronic influences and suggests that strong imine coordination can allow it to compete with the more rapid insertion of alkenes. This reactivity has been employed to develop a CO/alkene/CO/imine insertion cascade to synthesize five- and six-membered-ring lactams.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry