Rollover‐Assisted C(sp 2 )C(sp 3 ) Bond Formation

Rollover cyclometalation involves bidentate heterocyclic donors, unusually acting as cyclometalated ligands. The resulting products, possessing a free donor atom, react differently from the classical cyclometalated complexes. Taking advantage of a “rollover”/“retro‐rollover” reaction sequence, a succession of oxidative addition and reductive elimination in a series of platinum(II) complexes [Pt(N,C)(Me)(PR 3 )] resulted in a rare C(sp 2 )C(sp 3 ) bond formation to give the bidentate nitrogen ligands 3‐methyl‐2,2′‐bipyridine, 3,6‐dimethyl‐2,2′‐bipyridine, and 3‐methyl‐2‐(2′‐pyridyl)‐quinoline, which were isolated and characterized. The nature of the phosphane PR 3 is essential to the outcome of the reaction. This route constitutes a new method for the activation and functionalization of CH bond in the C(3) position of bidentate heterocyclic compounds, a position usually difficult to functionalize.