- Sterically Demanding Oxidative Amidation of α-Substituted Malononitriles with Amines Using O2
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An efficient amidation method between readily available 1,1-dicyanoalkanes and either chiral or nonchiral amines was realized simply with molecular oxygen and a carbonate base. This oxidative protocol can be applied to both sterically and electronically challenging substrates in a highly chemoselective, practical, and rapid manner. The use of cyclopropyl and thioether substrates support the radical formation of α-peroxy malononitrile species, which can cyclize to dioxiranes that can monooxygenate malononitrile α-carbanions to afford activated acyl cyanides capable of reacting with amine nucleophiles.
- Li, Jing,Lear, Martin J.,Hayashi, Yujiro
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supporting information
p. 9060 - 9064
(2016/07/26)
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- The Synthesis of Some Lipophilic Tetradentate Ligands for Use in the Formation of Metal-Linked Polymers
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Two lipophilic tetradentate ligands, 5,5'-di-t-butyl- and 5,5'-dihexyl-2,2'-bipyrimidine, were prepared via either Ullmann or nickel(0)-promoted reactions in low but useful yields.Approaches towards the synthesis of lipophilic ligands based on 2,2'-biimidazole, namely 4,4',5,5'-tetrabutyl-2,2'-biimidazole (from decane-4,5-dione) and various 4,4',5,5'-tetra(arylamino)-2,2'-biimidazoles (from 4,4',5,5'-tetrabromo-2,2'-biimidazole and arylamines), and a 2,2'-bibenzimidazole, 5,5',6,6'-tetra(octyloxy)-2,2'-bibenzimidazole (from N,N'-bisoxamide), were uniformly unsuccessful for preparing the 2,2'-biheteroaryl compounds.
- Crossley, Maxwell J.,Gorjian, Sargon,Sternhell, Sever,Tansey, Kerrie M.
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p. 723 - 738
(2007/10/02)
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- Resonanzstabilisierung von Alkylradikalen durch zwei geminale Cyangruppen
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Effects of Substituents on the Strength of C-C bonds, 10. - Resonance Stabilization of Alkyl Radicals by Two Geminal Cyano groups The activation parameters of the homolytic cleavage of the Cq-Cq bonds of several dialkylated malonodinitriles (2-5) and of 1,1,2,2-tetracyanoethane (7) and the heat of dissociation of 6 in solution have been determined.Together with the ground state strain of the radical precursor (obtained from the heats of combustion or EFF calculations) the steric influence on the dissociation process has been determined.The resonancestabilization energy of α,α'-dicyanoalkyl radicals then calculated was (12.4 +/- 0.9) kcal/mol.This result is discussed within the concept of capto-dative stabilization.The destabilizing interaction of two geminal cyano groups is apparently the same in the ground state of 2-7 and the radicals generated from them.
- Pakusch, Joachim,Beckhaus, Hans-Dieter,Ruechardt, Christoph
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p. 1191 - 1198
(2007/10/02)
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- Facile Carbon-Carbon Bond Heterolysis. SN1-E1 Reactions of t-Cumyl and t-Butyl Substituted Tricyanomethanes
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The tricyanomethanide ion C(CN)3- was found to serve as an efficient leaving group anion to generate unstable carbocations such as t-cumyl and t-butyl cations, the ability of carbon-terminated leaving groups so far examined being in the order C(CN)2N=NC6H4NO2-p C(CN)3 C(CN)2NO2.
- Hirota, Hiroshi,Mitsuhashi, Tsutomu
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p. 803 - 806
(2007/10/02)
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