Treatment of (2-hydroxymethylnorbornadiene)cyclopentadienylrhodium (V) with sulfuric acid offers the stable cationic complex XI, which can be isolated as PF 6 − or BF 4 −. 1H and 13C NMR data indicate that in cation XI the bicyclic ligand is bound to the metal via η 2-ethylene and η 3-allyl bonds, including an exocyclic methylene carbon. The structure of complex XI is supported by a single-crystal X-ray diffraction study of its PF 6 − salt. Reaction of diastereomeric carbinols ψ- exo-VI and ψ- endo-Rh {η 4-C 7H 7CH(OH)Me} (η 4-C 5H 5) (VII) proceeds with absolute stereospecificity to form syn-XII and anti-[Rh(η 5-C 7H 7CHMe)(η 5a-C 5H 5)] + (XIII) isomers, respectively. Similarly, cation [Rh(η 5-C 7H 7CHPh)(η 5-C 5H 5)] + (XV), derived from ψ- endo-Rh {η 4-C 7H 7CH(OH)Ph}(η 5-C 5H 5) (IX), has the syn configuration. However, the same reaction of the ferrocenyl-substituted carbinol ψ- endo-Rh {η 4-C 7H 7CH(OH)Fc} (η 5-C 5H 5) (X) leads to mixture of two isomeric complexes, syn-(XVI) and anti-[Rh(η 5-C 7H 7CHFc)(η 5-C 5H 5)] + (XVII), in a ratio of 4 1 . The absolute stereospecificity and the relative facility with which the formation of cationic η 3-allylic complexes from carbinols VI, VII and IX takes place are due to the nucleophilic participation of a rhodium atom in stabilizing the electron-deficient center during the reaction. The disturbance of stereospecificity during the conversion of carbinol X to a cationic complex assumes the formation of an α-ferrocenylcarbenium ion (XIX) as an intermediate (a product of kinetic control). Owing to the relative non-hindrance of rotation around the exocyclic carboncarbon bond C(2)—C(8) in the carbenium ion XIX, the formation of a non-equal mixture of complexes XVI and XVII, the products of thermodynamic control of the reaction, takes place.