THE CHEMISTRY OF LAURENENE .16. INVESTIGATION OF THE MECHANISM OF A CATIONIC REARRANGEMENT

Some aspects of the mechanism of the acid-induced rearrangement of laurenan-2beta-ol have been deduced from deuterium-labelling studies. A key intermediate arises from two pathways, one involving a 1,4- and one a 1,5-hydride shift. Formation of this intermediate is partially suppressed by substitution of the migrating hydrogen by a deuterium. A proposed pathway which involves a 1,3-methyl migration has been disproved, and scrambling and loss of deuterium label has been accounted for in terms of equilibria involving lauren-1-ene and another previously reported rearrangement product. The rearrangement is strongly promoted in dichloromethane, and the product composition is highly solvent-dependent.