During Wolfe’s graduate career at MIT with Professor Stephen L. Buchwald, he was involved in developing dialkylbiaryl phosphine ligands (now referred to as "Buchwald ligands") that are highly efficient in palladium-catalyzed reactions.
One of these ligands – JohnPhos - was named after him and is now commercially available.

In general, JohnPhos is a ligand for the Buchwald-Hartwig Cross Coupling reaction, C-X bond formation, the Heck reaction and Suzuki-Miyaura coupling.
JohnPhos is a particularly effective ligand for the palladium-catalyzed amination of aryl chlorides, bromides, and triflates.
The ligand allows the reactions to take place at room-temperature, and performs well for a wide range of different substrate combinations at 80-110 °C, which includes chloropyridines and functionalized aryl halides and triflates.
JohnPhos is particularly useful for aminations of –neutral or electron rich aryl chlorides with a wide variety of amine coupling partners.
 An example of the catalytic amination of an aryl chloride with N-methylaniline at room temperature is shown in Scheme 3.

Although the high reactivity of the ligand is not completely understood, Buchwald et al.
suggest some structural factors that contribute to their effectiveness: the electron rich phosphine group may help the acceleration of the oxidative addition step, the steric bulk of the ligands may accelerate the C-N bond forming reductive elimination, and the π-system of the ortho aromatic group on the ligand may participate in an interaction with the unoccupied metal d-orbital.
Another hypothesis is that the metal-arene interaction could stabilize the catalyst.
The arene from the aryl halide is forced to orient perpendicularly to the N-Pd bond, which should stereoelectronically favor reductive elimination.
During Wolfe’s graduate career at MIT with Professor Stephen L. Buchwald, he was involved in developing dialkylbiaryl phosphine ligands (now referred to as "Buchwald ligands") that are highly efficient in palladium-catalyzed reactions. One of these ligands – JohnPhos - was named after him and is now commercially available.
In general, JohnPhos is a ligand for the Buchwald-Hartwig Cross Coupling reaction, C-X bond formation, the Heck reaction and Suzuki-Miyaura coupling. JohnPhos is a particularly effective ligand for the palladium-catalyzed amination of aryl chlorides, bromides, and triflates. The ligand allows the reactions to take place at room-temperature, and performs well for a wide range of different substrate combinations at 80-110 °C, which includes chloropyridines and functionalized aryl halides and triflates. JohnPhos is particularly useful for aminations of –neutral or electron rich aryl chlorides with a wide variety of amine coupling partners.  An example of the catalytic amination of an aryl chloride with N-methylaniline at room temperature is shown in Scheme 3.
Although the high reactivity of the ligand is not completely understood, Buchwald et al. suggest some structural factors that contribute to their effectiveness: the electron rich phosphine group may help the acceleration of the oxidative addition step, the steric bulk of the ligands may accelerate the C-N bond forming reductive elimination, and the π-system of the ortho aromatic group on the ligand may participate in an interaction with the unoccupied metal d-orbital. Another hypothesis is that the metal-arene interaction could stabilize the catalyst. The arene from the aryl halide is forced to orient perpendicularly to the N-Pd bond, which should stereoelectronically favor reductive elimination.
John P. Wolfe