The liquid-phase acetoxylation and acetoxylation/hydration of camphene (1) in homogeneous or heterogeneous systems catalyzed by dissolved or silica-supported heteropoly acid H3PW12O40 (PW) in AcOH/H2O solutions (0-10 vol.% H2O) have been studied. Isobomyl acetate (2a) and isoborneol (3a) are the main reaction products which have been obtained with an almost 100% total selectivity. No oligomerization of camphene has been observed. PW shows a much higher catalytic activity than conventional acid catalysts such as H2SO4 and Arnberlyst-15. It can be recovered without neutralization and reused. (C) 2002 Elsevier Science B.V All rights reserved.