However, when a harsher oxidation process was applied, using hydrogen peroxide (H 2 O 2 ) and sodium hydroxide (NaOH), we observed the formation of the γ-lactone product 10 (Figure ). Product 10 was achieved in excellent yield within only a 3-minute reaction time. In this scenario, we assumed that the geminal-Bpin,Bpin unit (in 3) initially underwent an oxidation reaction, in which 3 was in-situ converted to carbonyl group to give 9 , followed by a Baeyer-Villiger type-oxidation reaction to finally yield the γ-lactone products 10 (Figure ). Afterward, we sought to generalize these oxidations process. Both reactions were tolerant of various of gemdiborylcyclobutanes 3p-3s, 3a, 3x and 3v, bearing different substituents, forming the corresponding oxygenated products 9b-9d and 10b-10e in good yields (Figure ).