The structures of the norbornenyl and norbornyl sulfones more stable than the exo anions. There is good agreement between the optimized structures of the free anions and the exo-5, endo-5 and endo-6 have been determined experimentally, by X-ray analysis, and theoretically by ab experimentally determined structures of the anions of the contact ion pairs in the crystal. Reactions of 3 and 4 with DX, initio calculations (HF/6-31+G*). X-ray crystal structure analyses of the lithiated allylic norbornenyl and norbornyl MeI, EtI, nPrI and nHeI occurred at the C2 atom under the selective formation of the corresponding endosulfones endo-sulfones endo-3/ent-endo-3•2diglyme and endo-4/ent-endo-4•2diglyme revealed dimeric O-Li contact ion pairs devoid of 8a-e and endo-9a-e, respectively, in all cases. Thus, an earlier report on the selective formation of the exosulfone C-Li bonds. The anions of endo-3/ent-endo-3•2diglyme and endo-4/ent-endo-4•2diglyme adopt both the endo exo-9b in the reaction of 4 with MeI has to be revised. Product ratios were independent of the configuration of the conformation (C2-S) and are characterized by in the exo direction pyramidalized anionic C atoms. The degree of starting sulfones and varied with the nature of the electrophile. Selectivities were highest in the case of the pyramidalization of the C2 atom of 3 is higher than that of 4. Ab initio optimizations (HF/6-31+G*) of the structures of the norbornyl species 4. Reaction of 3 with PhCHO occurred at the α position (C2) to afford the alcohols endo-8f and exo-8f anions of methylenenorbornene I and methylenenorbornane II resulted in local minima featuring non-planar C2 atoms (88:12) as single diastereomers and at higher temperatures at the γ position (C8), whereas reaction of 4 with PhCHO which are pyramidalized in the exo direction in both cases, but to different degrees. In both cases cryoscopy of 3 and 4 took place at the γ position even at low temperatures. Methylation of endo-5 and exo-5 at -105 °C by both the in THF at -108.5 °C revealed approximately 1:1 mixtures of monomers and dimers. The sulfones exo-5, endo-5, exo-6 stepwise method and by the in situ method gave different ratios of exo-and endo-methylation products. The and endo-6 as well as the lithiosulfones 3 and 4 were studied by NMR spectroscopy. 1 H-NMR (400 MHz), 13 C-NMR (100 selectivities of reaction of 3 and 4 with electrophiles have been rationalized by the Curtin-Hammett/Winstein-Holness MHz) and 6 Li-NMR (44 MHz) spectroscopy of 3 and 4 at -100 °C in [D] 8 THF revealed in each case only one set of signals, concepts. It is proposed that endo-3 (endo-4) and exo-3 (exo-4) are conformationally labile on the time scale defined by independent of the configuration of the starting sulfones. This indicates in both cases that attainment of both the the rate of their reactions with electrophiles, and are attacked by electrophiles with high selectivities from the exo and the monomer-dimer and the endo/exo equilibria of 3 and 4 is fast on the NMR time scale. According to 6 Li{ 1 H}-and 1 H{ 1 H}-endo face, respectively, because of the shielding by the phenyl group and the direction of the pyramidalization of the NOE experiments of 3 and 4 the monomeric and dimeric species endo-3 and endo-4, having endo anions, seem to be anionic C atom. Preferential formation of the endo sulfones is thus ascribed to exo attack of electrophiles on endo-3 preferred in THF solution. Ab initio calculations of the anions of 3 and 4 resulted in structures endo-3(-Li + ), exo-3(-Li + ), (endo-4) being faster than endo attack on exo-3 (exo-4) because of Houk's staggering effect. Methylation of 3 and 4 endo-4(-Li + ) and exo-4(-Li + ) (HF/6-31+G*), whose atomic point charges were calculated by the method of Kollman et by the in situ method showed 3, whose C2 atom is stronger pyramidalized, to be more reactive than 4. The base-al. The C2 atoms of endo-3(-Li + ) and endo-4(-Li + ) are pyramidalized in the exo direction whereas the C2 atoms of catalyzed H/D exchange of sulfones endo-5, exo-5, endo-6 and exo-6 with NaOCD 3 in CD 3 OD proceeded in all cases exo-3(-Li + ) and exo-4(-Li + ) are pyramidalized in the endo direction. According to the calculations, the endo anions are with a high degree of retention of configuration.