Enhancing Metalating Efficiency of the Sodium Amide NaTMP in Arene Borylation Applications

Though LiTMP (TMP=2,2′,6,6′‐tetramethylpiperidide) is a commonly used amide, surprisingly the heavier NaTMP has hardly been utilised. Here, by mixing NaTMP with tridentate donor PMDETA (N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine), we provide structural, and mechanistic insights into the sodiation of non‐activated arenes (e.g. anisole and benzene). While these reactions are low yielding, adding B(OiPr)(3) has a profound effect, not only by intercepting the C(Ar)‐Na bond, but also by driving the metalation reaction towards quantitative formation of more stabilized sodium aryl boronates. Demonstrating its metalating power, regioselective C2‐metalation/borylation of naphthalene has been accomplished contrasting with single‐metal based protocols which are unselective and low yielding. Extension to other arenes allows for in situ generation of aryl boronates which can then directly engage in Suzuki–Miyaura couplings, furnishing a range of biaryls in a selective and efficient manner.