Catalytic asymmetric synthesis of 3-aryl phthalides enabled by arylation-lactonization of 2-formylbenzoates.

The catalytic asymmetric synthesis of 3-aryl phthalides is reported through a sequential asymmetric arylation-lactonization reaction. The reaction is enabled by a boron-zinc exchange to generate reactive arylating agents, which react with 2-formylbenzoates in the presence of a chiral amino naphthol ligand. The enantiodetermining step is the arylation of the aldehyde, which then undergoes a lactonization event to yield the corresponding phthalides in good yields and enantioselectivities.