作者:Stephen F. Nelsen、Yichun Wang
DOI:10.1021/jo00090a028
日期:1994.6
Eleven bis(N,N'-bicyclic) diazenium dications were generated from the corresponding hydrazines by NOPF6 oxidation. Their reactivity depends greatly upon the sizes of the bicyclic rings. (We designate bicyclic ring size using the number of atoms in the two bridges in addition to the dinitrogen bridge all the compounds share.) Compounds with 21 rings alkylate acetonitrile at 240 K by opening a C-alpha-N+ bond to produce a trialkyldiazenium cation, with Delta G(double dagger) for the reaction increasing by at least 5.5 kcal/mol as the second bicyclic ring size increases. Compounds with an unsaturated bridge also alkylate acetonitrile; 22/u22(2+) only cleaves the u22 bridge and reacts faster than 21/22(2+), which only cleaves the 21 bridge. C-alpha-N+ cleavage of 22 and larger rings by acetonitrile has not been observed. 21/22(2+) is significantly more acidic than 22/22(2+), but both are beta-deprotonated by pyridine to produce aminoaziridinium cations at 240 K. At least mostly the exo 21 ring proton is lost from 21/22(2+). Dications with 23 and 24 bridges deprotonate at the alpha-carbon instead of the beta-carbon, and 22/23(2+) is slightly more kinetically acidic than 21/22(2+). 22/24(2+) is deprotonated rapidly by ether at 235 K.