L'hydrolyse acide des diazocétones alcoylées: Formation d'ions α‐acylcarbonium secondaires

Hydrolysis of secondary diazoketones CH3COCN2R (R  Me, Et, isopropyl) by aqueous perchloric acid is characterized by rate‐determining protonation demonstrated by solvent isotope effects kD2O/kH2O = 0,4–0,6 and by the intervention of general acid catalysis. The product determining step, yielding keto‐alcohols and keto‐olefines, is independent of added nucleophiles; this is interpreted as resulting from the intermediate formation of (more or less free) αhyphen;ketocarbonium is ions. The hydride shift observed wih III (R = isopropyl) supports this interpretation. The difference between hydrolysis of primary and of secondary diazoketones is discussed.