The effects of ring size and substituents on the rates of acid-catalysed hydrolysis of five- and six-membered ring cyclic ketone acetals

A series of sterically similar five- and six-membered ring cyclic diol-derived ketone acetals have been prepared and their rates of acid-catalysed hydrolysis examined. The rates of hydrolysis are substantially affected by acetal ring conformational stereoelectronic effects and resonance effects depending upon the substituents on the parent ketone; an A1 mechanism of hydrolysis explains the observed effects. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).