9-Cyclopropyl-9-xanthyl cation

The 9-Cyclopropyl-9-xanthyl cation 33 is so stable that the positive charge is hardly delocalized into the cyclopropyl group. The alpha and beta hydrogens of the cyclopropyl group show absorptions at <5 H 2.96,1.38 and 1.96, comparable to that of cyclopropylam-monium ion (<5 H 2.93 and 0.93), rather than a typical cyclopropylcarbinyl cation, such as dimethylcyclopropylcarbinylcation (<5 H 3.4, 4.0)64. 

---