Journalartikel

Jahr der Veröffentlichung: 1999

Seiten: 855-860

Zeitschrift: European Journal of Organic Chemistry

Bandnummer: 1999

Heftnummer: 4

ISSN: 1434-193X

Verlag: Wiley

Abstract: 
The oxidation of 3,6-dehydrohomoadamantane (1) was achieved under chemical (NO+BF4-/EtOAc, NO+OAc-/Ac2O, and NO+BF4-/CH3CN), photochemical (photoexcited 1,2,4,5-tetracyanobenzene), and electrochemical (Pt anode, CH3CN, NH4BF4) conditions. Supporting ab initio [density functional theory (BLYP) and Moller-Plesset perturbation theory (MP2)] computations utilizing standard basis sets, 6-31G* (optimizations) and 6-311+G* (single-point energy evaluations), agree with the experimental results implicating the involvement of the same radical cation intermediates in the activation processes. Isomeric radical cations formed from different precursors can equilibrate with low barriers (2.0-11.7 kcal mol(-1)) and lead to common products. The computed and experimental adiabatic ionization potential of adamantane shows that activation with NO+BF4- is also likely to occur through the adamantyl radical cation. Hence, the bonds need not be attacked directly by the electrophile in the C-H or C-C activation of alkanes with relatively low ionization potentials.