Water Participated Dual C(sp 3 )−C(sp 3 ) Bond Cleavage of Cyclobutanones Catalyzed by Lewis Acid

Abstract Lewis acid‐catalyzed ring‐opening reactions of cyclobutanones were mostly achieved through cleavage of a single C2−C3 bond to deliver cyclic products. Herein, an unprecedented Lewis acid catalyzed synergistic cleavage of both C2−C3 bonds in 3‐arylcyclobutanones was realized under participation of water, providing a series of aryl alkyl ketones in mild conditions. A broad scope of substrates decorated with various substituents were well accommodated. Mechanistic proposal including the function of water was unambiguously validated by experimental verification.