Switching to the non-PFAS-containing fluorosulfate leaving group, together with a Pd oxidative addition complex: rapid aminations of functionalized aromatics in water

Aryl fluorosulfates of varying complexities have been used in amination reactions in water using a new Pd oxidative addition complex (OAC) developed specifically to match the needs of the fine chemicals industry, not only in terms of functional group tolerance but also reflecting time considerations associated with these important C–N couplings. Also especially noteworthy is that they replace both PFAS-related triflates and nonaflates, which are today out of favor due to recent government regulations. The new complex based on the BippyPhos ligand is used at low loadings and under aqueous micellar conditions. Moreover, it is easily prepared and stable to long-term storage. DFT calculations on the OAC precatalyst compare well with the X-ray structure of the crystals with -complexation to the aromatic system of the ligand and also confirm the NMR data showing a mixture of conformers in solution that differ from the X-ray structure in rotation of the phenyl and t-butyl ligand substituents. An extensive variety of coupling partners, including pharmaceutically relevant APIs, readily participate under mild and environmentally responsible reaction conditions