Biaryl monophosphine ligands in palladium-catalyzed C–N coupling: An updated User's guide

Over the past three decades, Pd-catalyzed cross-coupling reactions have become a mainstay of organic synthesis. In particular, catalysts derived from biaryl monophosphines have shown wide utility in forming C–N bonds under mild reaction conditions. This work summarizes a variety of C–N cross-coupling reactions using biaryl monophosphines as supporting ligands, with the goal of directing synthetic chemists towards the ligands and conditions best suited for a particular coupling. When I learned that I had received the 2018 Tetrahedron Prize for Creativity in Organic Chemistry, jointly with Professor John F. Hartwig of UC Berkeley, I felt a sense of great accomplishment. Accomplishment not specifically for me, but by my research group (and that of John's) in developing new chemistry that was both intrinsically interesting and of practical utility. The latter aspect is the reason that we have chosen to write this review to help practitioners in the field utilize palladium-catalyzed C–N coupling reactions more broadly, efficiently, and predictively in their own research efforts. We note that while we have limited this review to reactions using biaryl phosphine ligands, that many other good alternatives exist.