Pathway to Construct α-Acyloxy Esters by B(C 6 F 5 ) 3 -Catalyzed O-H Insertion of Carboxylic Acids with Sulfoxonium Ylides.

We report the first example of B(C 6 F 5 ) 3 -catalyzed O-H insertion reaction of sulfoxonium ylides and carboxylic acids, achieving efficient construction of diester moieties under metal-free condition. This protocol is characterized by broad substrate tolerance, particularly for various phenylacetic acids, and good compatibility with water/air condition, which is superior to most other methods.