title: Studies of 9-fluorenyl carbocations. intramolecular hydride migration in a substituted 9-fluorenyl carbocation.
abstract: The substituted fluorenyl cation, 9-(diphenylmethyl)fluoren-9-yl cation (4), is formed under stable ion conditions (low temperature/strong acid) from its corresponding alcohol 3. This ion is transformed to a substituted diphenyl methyl cation 8 at ambient temperature via an apparent 1,2-hydrogen shift. Irradiation of 9-(diphenylmethyl)fluoren-9-ol in methanol gives products derived from the corresponding cation along with radical-derived products from C-C and C-O homolysis processes. The laser flash photolysis of this alcohol gave a transient corresponding to cation 4. All of the photoproducts are derived from cation 4 or radical pathways. High level MO calculations point to a high barrier (23.8 kcal x mol(-1)) for the 1,2-hydride shift. This barrier is the consequence of the minimum energy conformation of this fluorenyl cation which is less than ideal for the periplanar geometry necessary for this process.
authors: Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada.
authors: G
authors: G
authors: Mladenova
authors: L
authors: L
authors: Chen
authors: C F
authors: CF
authors: Rodriquez
authors: K W
authors: KW
authors: Siu
authors: L J
authors: LJ
authors: Johnston
authors: A C
authors: AC
authors: Hopkinson
authors: E
authors: E
authors: Lee-Ruff