14950-46-0Relevant articles and documents
Reactions of Bis(N,N'-bicyclic) Diazenium Dications
Nelsen, Stephen F.,Wang, Yichun
, p. 3082 - 3090 (1994)
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 compound share.) Compounds with rings alkylate acetonitrile at 240 K by opening a Cα-N(+) bond to produce a trialkyldiazenium cation, with ΔG(excit.) 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 bridge and reacts faster than 21/22(2+), which only cleaves the bridge.Cα-N(+) cleavage of and larger rings by acetonitrile has not been observed. 21/22(2+) is significantly more acidic than 22/22(2+), but both are β-deprotonated by pyridine to produce aminoaziridinium cations at 240 K.At least mostly the exo ring proton is lost from 21/22(2+).Dications with and bridges deprotonate at the α-carbon instead of the β-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.
Combined effects on selectivity in Fe-catalyzed methylene oxidation
Chen, Mark S.,White, M. Christina
scheme or table, p. 533 - 571 (2010/10/05)
Methylene C-H bonds are among the most difficult chemical bonds to selectively functionalize because of their abundance in organic structures and inertness to most chemical reagents. Their selective oxidations in biosynthetic pathways underscore the power of such reactions for streamlining the synthesis of molecules with complex oxygenation patterns. We report that an iron catalyst can achieve methylene C-H bond oxidations in diverse natural-product settings with predictable and high chemo-, site-, and even diastereoselectivities. Electronic, steric, and stereoelectronic factors, which individually promote selectivity with this catalyst, are demonstrated to be powerful control elements when operating in combination in complex molecules. This small-molecule catalyst displays site selectivities complementary to those attained through enzymatic catalysis.
Formation of Dicarbonyl Compounds in the Flash Vacuum Pyrolysis of Saturated Bicyclic Peroxides
Bloodworth, A. J.,Baker, David S.,Eggelte, Henny J.
, p. 1034 - 1036 (2007/10/02)
Under flash vacuum pyrolysis, dioxabicycloalkanes (n = 3,4, and 5) isomerise to keto-aldehydes, MeCOnCHO, whereas dioxabicycloalkanes (n = 2,3, and 4) fragment to give, by loss of hydrogen and ethylene, mixtures of cycloalkane-1,4-diones and dialdehydes, OHCnCHO.
