Indoline Synthesis via Coupling of Phenethyl Grignard Reagents with Organoazides Mediated by (Alkylphosphine)nickel(II) Complexes

The room-temperature reaction of (PMe 3 ) 2 Ni(CH 2 CMe 2 - o -C 6 H 4 ) ( 3 ) with 3 equiv of p -tolyl azide (TolN 3 ) results in evolution of N 2 and clean formation of the N - p -tolylindoline derivative TolNCH 2 CMe 2 - o -C 6 H 4 ( 4a ), isolated in 82% yield. The reaction almost certainly proceeds via insertion of an “NTol” fragment from TolN 3 into the Ni−C(aryl) bond to give an intermediate azametallacycle [L n Ni(NTol- o -C 6 H 4 CMe 2 CH 2 )] ( 5 ), which then undergoes C,N-reductive elimination to afford the indoline 4a .