Synthesis of neutral nickel-methyl complexes with monodentate imines and their sequential insertion of carbon monoxide and imine

摘要

Neutral nickel-imine complexes of the form (NO)Ni(R)(R~1NC(H) R~2) (NO = salicylaldiminato; R = CH_3, Ph; R~1 = alkyl; R~2 = aryl) can be prepared by the reaction of (tmeda)Ni(CH_3))_2, imine and the corresponding salicylaldiminato ligand. The addition of carbon monoxide to these complexes lead to the in situ generation of the corresponding nickel-acyl complexes. With N-methyl or N-benzyl substituted imines, these complexes reductively eliminate the phenolic and acyl ligands to generate esters. However, the less sterically encumbered 3,4-dihydroisoquinoline can couple with the nickel-acyl ligand to form 1,2-diamides in high yield. In situ ~1H NMR analysis suggests this reaction occurs via insertion of imine into the nickel-acyl bond to form a nickel-bound amide complex. Figure Presented.