Ring size effects in the neophyl rearrangement. VIII. Synthesis and solvolysis of 1-methyl-2,3-benzocycloalkenylcarbinyl tosylates

Abstract

l-Methyl-2,3-benzocycloalkenylcarbinyl tosylates 5 were synthesized and their solvolytic reactivity was determined. Neither in acetolysis nor in hydrolysis in 60% acetone was a ring size effect of any significance evidenced. The reactivities mirrored those of the unmethylated analogs 3. Products from 5 were totally rearranged via aryl ring migration indicating that aryl participation was essentially the only solvolysis pathway. The opposing factors in 3 of strain in the phenonium ion intermediate vs. conformational effects are discussed together with a reactant strain effect in 5. The conclusion is drawn that the three effects are balanced to produce the similarity in behavior between the two sets of tosylates. Some years ago Huisgen and coworkers4 observed