4 research outputs found

    Completely N<sup>1</sup>-Selective Palladium-Catalyzed Arylation of Unsymmetric Imidazoles: Application to the Synthesis of Nilotinib

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    The completely N<sup>1</sup>-selective Pd-catalyzed arylation of unsymmetric imidazoles with aryl halides and triflates is described. This study showed that imidazoles have a strong inhibitory effect on the in situ formation of the catalytically active Pd(0)–ligand complex. The efficacy of the N-arylation reaction was improved drastically by the use of a preactivated solution of Pd<sub>2</sub>(dba)<sub>3</sub> and <b>L1</b>. From these findings, it is clear that while imidazoles can prevent binding of <b>L1</b> to Pd, once the ligand is bound to the metal, these heterocycles do not displace it. The utility of the present catalytic system was demonstrated by the regioselective synthesis of the clinically important tyrosine kinase inhibitor nilotinib

    Palladium-Catalyzed Amination of Unprotected Five-Membered Heterocyclic Bromides

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    An efficient method for the palladium-catalyzed amination of unprotected bromoimidazoles and bromopyrazoles is presented. The transformation is facilitated by the use of our newly developed Pd precatalyst based on the bulky biarylphosphine ligand <i>t</i>BuBrettPhos (<b>L4</b>). The mild reaction conditions employed allow for the preparation of a broad scope of aminoimidazoles and aminopyrazoles in moderate to excellent yields

    Investigating the Dearomative Rearrangement of Biaryl Phosphine-Ligated Pd(II) Complexes

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    A series of monoligated L·Pd<sup>II</sup>(Ar)­X complexes (L = dialkyl biaryl phosphine) have been prepared and studied in an effort to better understand an unusual dearomative rearrangement previously documented in these systems. Experimental and theoretical evidence suggest a concerted process involving the unprecedented Pd<sup>II</sup>-mediated insertion of an aryl group into an unactivated arene