Cationic Rearrangements of an endo}-Cyclopropyl Methanol System Incorporated in a Benzonorbornadiene System

Chloride 18 (47%) and alcohol 21 (44%) were isolated from the reaction of alcohol 20 with SOCl2. Cyclopropylcarbinyl -- cyclopropylcarbinyl rearrangement leads to chloride 22, which hydrolyses on separation to give alcohol 21. Chloride 18 results from cyclopropyl -- allylcarbinyl rearrangement, followed by a 1,2 -- aryl shift (sequential rearrangement). Syntheses of compounds 23 and 24 support the structures. The behaviour of 20 differs from that of exo isomer 14, probably due to the nature of the intermediates in these reactions.

Cationic Rearrangements of an endo}-Cyclopropyl Methanol System Incorporated in a Benzonorbornadiene System

Chloride 18 (47%) and alcohol 21 (44%) were isolated from the reaction of alcohol 20 with SOCl2. Cyclopropylcarbinyl -- cyclopropylcarbinyl rearrangement leads to chloride 22, which hydrolyses on separation to give alcohol 21. Chloride 18 results from cyclopropyl -- allylcarbinyl rearrangement, followed by a 1,2 -- aryl shift (sequential rearrangement). Syntheses of compounds 23 and 24 support the structures. The behaviour of 20 differs from that of exo isomer 14, probably due to the nature of the intermediates in these reactions.