Rearrangements of pinane derivatives. Part I. Products of acid catalysed hydration of α-pinene and β-pinene

The acid-catalysed hydration of α-pinene and β-pinene has been shown to proceed through a common intermediate stage, probably involving two equilibrating ions. These ions can eliminate to give α-pinene, or undergo ring expansion to bornane and fenchane derivatives, or ring opening to p-methane derivatives. The formation and subsequent rearrangements of the products have been followed.