A General Protocol for the Broad-Spectrum Cross-Coupling of Nonactivated Sterically Hindered 1° and 2° Amines

While notable advances have been reported for the metal-catalyzed cross-coupling of bulky amines, to date no set of reported conditions has proven general for both hindered and unactivated primary and secondary amines. Examples that are reported with Pd catalysts invariably involve aggressive alkoxide bases in order to provide the necessary “push” required to couple these challenging substrates. Consequently, few, if any, base-sensitive functional groups (e.g., esters, ketones, cyano groups) are included in published reports involving such substrates. Herein we disclose the use of Pd-PEPPSI-IPentCl3-chloropyridine precatalyst with the mild, yet soluble base sodium butylated hydroxytoluene (NaBHT) in one single protocol that can couple a broad scope of hindered and unactivated primary and secondary amines to produce functionalized products in high yields.