63674-11-3Relevant articles and documents
H2 Activation by Non-Transition-Metal Systems: Hydrogenation of Aldimines and Ketimines with LiN(SiMe3)2
Elliott, Daniel C.,Marti, Alex,Mauleón, Pablo,Pfaltz, Andreas
, p. 1918 - 1922 (2019/01/16)
In recent years, H2 activation at non-transition-metal centers has met with increasing attention. Here, a system in which H2 is activated and transferred to aldimines and ketimines using substoichiometric amounts of lithium bis(trimethylsilyl)amide is reported. Notably, the reaction tolerates the presence of acidic protons in the α-position. Mechanistic investigations indicated that the reaction proceeds via a lithium hydride intermediate as the actual reductant.
Phosphine-Free Well-Defined Mn(I) Complex-Catalyzed Synthesis of Amine, Imine, and 2,3-Dihydro-1 H-perimidine via Hydrogen Autotransfer or Acceptorless Dehydrogenative Coupling of Amine and Alcohol
Das, Kalicharan,Mondal, Avijit,Pal, Debjyoti,Srivastava, Hemant Kumar,Srimani, Dipankar
supporting information, p. 1815 - 1825 (2019/04/30)
The application of nontoxic, earth-abundant transition metals in place of costly noble metals is a paramount goal in catalysis and is especially interesting if the air- and moisture-stable ligand scaffold is used. Herein, we report the synthesis of amines/imines directly from alcohol and amines via hydrogen autotransfer or acceptorless dehydrogenation catalyzed by well-defined phosphine-free Mn complexes. Both imines and amines can be obtained from the same set of alcohols and amines using the same catalyst, only by tuning the reaction conditions. The amount and nature of the base are found to be a highly important aspect for the observed selectivity. Both the primary and secondary amines have been employed as substrates for the N-alkylation reaction. As a highlight, we showed the chemoselective synthesis of resveratrol derivatives. Furthermore, the Mn-catalyzed dehydrogenative synthesis of structurally important 2,3-dihydro-1H-perimidines has also been demonstrated. Density functional theory calculations were also carried out to model the reaction path and to calculate the reaction profile.
Copper-catalyzed ligand free ring-opening amination of gem-fluorohalocyclopropanes – An efficient route toward 2-fluoroallylamines
Novikov, Maxim A.,Ibatov, Yaroslav A.,Volchkov, Nikolai V.,Lipkind, Maria B.,Semenov, Sergei E.,Nefedov, Oleg M.
, p. 58 - 72 (2017/01/18)
Ring-opening amination of gem-chlorofluoro- and gem-bromofluorocyclopropanes with secondary alkyl, aryl amines or hydroxylamines catalyzed by copper(I) or copper(II) compounds with no additional ligands affords tertiary 2-fluoroallylamines or hydroxylamines in moderate to excellent yields. The reaction pathway involves isomerization of gem-fluorohalocyclopropanes to 2-fluoroallyl halides followed by in situ nucleophilic substitution of a halide by an N-nucleophile. The p-methoxyphenyl (PMP) protective group is efficient in the preparation of secondary 2-fluoroallylamines by this method. Primary 2-fluoroallylamines can only be obtained by a stepwise protocol including CuX-catalyzed isomerization of gem-fluorohalocyclopropanes to 2-fluoroallylic halides followed by amination.
