93013-27-5Relevant articles and documents
Heavy-Atom Kinetic Isotope Effects in the Acid-Catalyzed Rearrangement of N-2-Naphtyl-N'-phenylhydrazine. Rearrangement Is Shown To Be a Concerted Process
Shine, Henry J.,Kupczyk-Subotkowska, Lidia,Subotkowski, Witold
, p. 6674 - 6678 (1985)
Heavy-atom kinetic isotope effects (KIE) have been measured in the acid-catalyzed rearrangement of N-2-naphthyl-N'-phenylhydrazine (1) into 1-(o-aminophenyl)-2-naphthylamine (2).A combination of whole-molecule-ion and isotope ratio mass spectrometry and scintillation counting has given KIE for 15N, 13C, and 14C.Use of 1 and whole-molecule-ion mass spectrometry gave a KIE of 1.0434 (for two 15N atoms).Use of 1 and isotope-ratio mass spectrometry gave a KIE of 1.0196 for one naturally abundant 15N atom and 1.0042 for one 13C atom.Use of 1 gave a KIE of 1.0142 for one 14C atom.The results show that this rearrangement is a concerted process, namely a -sigmatropic shift.The transition state, furthermore, appears to be unsymmtetrical.That is, the extents of N-N bond breaking and C-C bond forming appear to be unequal.
Organocatalytic aryl-aryl bond formation: An atroposelective [3,3]-rearrangement approach to BINAM derivatives
Li, Gong-Qiang,Gao, Hongyin,Keene, Craig,Devonas, Michael,Ess, Daniel H.,Kürti, László
, p. 7414 - 7417 (2013/06/27)
Herein we disclose an organocatalytic aryl-aryl bond-forming process for the regio- and atroposelective synthesis of 2,2′-diamino-1,1′- binaphthalenes (BINAMs). In the presence of catalytic amounts of axially chiral phosphoric acids, achiral N,N′-binaphthyl hydrazines undergo a facile [3,3]-sigmatropic rearrangement to afford enantiomerically enriched BINAM derivatives in good to excellent yield. This transformation represents the first example of a metal-free, catalytic C(sp2)-C(sp2) bond formation between two aromatic rings with concomitant de novo atroposelective installation of an axis of chirality. Density functional calculations reveal that, in the transition state for C-C bond formation, the phosphoric acid proton of the catalyst is fully transferred to one of the N-atoms of the substrate, and the resulting phosphate acts as a chiral counterion.
BOND-FORMING CARBON KINETIC ISOTOPE EFFECTS IN BENZIDINE REARRANGEMENTS
Kupczyk-Subotkowski, Lidia,Shine, Henry J.,Subotkowski, Witold,Zygmunt, Jan
, p. 513 - 516 (2007/10/02)
Kinetic isotope effects (KIE, k(12)C/k(13)C) have been measured for the acid-catalyzed rearrangement of N-2-naphthyl-N'-phenylhydrazine, 1, into 1-(o-aminophenyl)-2-naphthylamine, 2, and of hydrazobenzene, 3, into benzidine, 4, and diphenyline, 5.The KIE for formation of 2 was 1.0177, confirming the earlier diagnosis of concerted rearrangement.From the (13)C KIE, k(12)C/k(14)C is calculated to be 1.0339, as compared with the value 1.0287 obtained earlier with (14)C labelling and compensated for both intra- and intermolecular isotopic competition.The KIE for forming 4 and 5 were 0.9945 and 0.9953, respectively.The KIE for formation of 5 is thus experimentally the same as that for forming 4, for which , of course, the measured KIE in this case must be unity.Thus, the KIE obtained for 5 is consistent with forming 5 by a non-concerted pathway.The new result with labelling is consistent with earlier findings with 4- and 4,4'-carbon labelling.Collectively, the present results are used to illustrate potential problems with measuring and interpreting carbon KIE for bond-forming reactions.
