Enantioselective Construction of Spiro Quaternary Carbon Stereocenters via Pd-Catalyzed Intramolecular α-Arylation.

We herein report the development of a sterically hindered and electron-rich P-chiral monophosphorus biaryl ligand that has enabled a general and efficient enantioselective intramolecular α-arylation, providing access to a wide series of [4.4], [4.5], and [4.6]-spirocycles with chiral benzylic quaternary carbons in high yields with good to excellent enantioselectivities. A pronounced water effect on enantioselectivity is observed.