1145-27-3Relevant articles and documents
Bridging amines with CO2: Organocatalyzed reduction of CO2 to aminals
Frogneux, Xavier,Blondiaux, Enguerrand,Thuéry, Pierre,Cantat, Thibault
, p. 3983 - 3987 (2015)
The four-electron reduction of CO2 in the presence of secondary aromatic amines is described for the first time to access aminals. Under metal-free hydrosilylation conditions, the four C-O bonds of CO2 are cleaved, and the organocatalysts are able to balance the reactivity of CO2 to promote the selective formation of two C-N and two C-H bonds. The methodology enables the formation of various symmetrical and unsymmetrical aminals.
Selective Ni-Catalyzed Hydroboration of CO2 to the Formaldehyde Level Enabled by New PSiP Ligation
Murphy, Luke J.,Hollenhorst, Helia,McDonald, Robert,Ferguson, Michael,Lumsden, Michael D.,Turculet, Laura
, p. 3709 - 3720 (2017)
The synthesis and characterization of group 10 metal pincer complexes supported by a new bis(indolylphosphino)silyl ligand are described, including the synthesis of Ni, Pd, and Pt hydride species. Solution NMR and single-crystal X-ray data revealed that a significant amount of structural variability is possible for such hydride complexes, particularly in the case of Ni, where terminal Ni-H as well as complexes involving η2-SiH coordination are both accessible and may even coexist, in ratios dependent on factors such as the nature of additional coligands, including N2 from the reaction atmosphere, as well as solvent and temperature. Nickel and palladium hydride complexes of this new ligand were found to exhibit divergent selectivity in the catalytic hydroboration of CO2 with pinacolborane (HBPin). While the Pd catalyst exhibited moderate activity for CO2 hydroboration to the formate level, the analogous Ni species exhibited unprecedented selectivity (97%) for hydroboration of CO2 to the formaldehyde level to provide the bis(boryl)acetal PinBOCH2OBPin in high yield, under mild conditions. The HBPin-derived bis(boryl)acetal can be successfully isolated and utilized as a source of methylene for the formation of C-N and C-P bonds.
Germyliumylidene: A Versatile Low Valent Group 14 Catalyst
Sarkar, Debotra,Dutta, Sayan,Weetman, Catherine,Schubert, Emeric,Koley, Debasis,Inoue, Shigeyoshi
supporting information, p. 13072 - 13078 (2021/08/09)
Bis-NHC stabilized germyliumylidenes [RGe(NHC)2]+ are typically Lewis basic (LB) in nature, owing to their lone pair and coordination of two NHCs to the vacant p-orbitals of the germanium center. However, they can also show Lewis acidity (LA) via Ge?CNHC σ* orbital. Utilizing this unique electronic feature, we report the first example of bis-NHC-stabilized germyliumylidene [MesTerGe(NHC)2]Cl (1), (MesTer=2,6-(2,4,6-Me3C6H2)2C6H3; NHC= IMe4=1,3,4,5-tetramethylimidazol-2-ylidene) catalyzed reduction of CO2 with amines and arylsilane, which proceeds via its Lewis basic nature. In contrast, the Lewis acid nature of 1 is utilized in the catalyzed hydroboration and cyanosilylation of carbonyls, thus highlighting the versatile ambiphilic nature of bis-NHC stabilized germyliumylidenes.
N-Heterocyclic Carbene-Stabilized Germa-acylium Ion: Reactivity and Utility in Catalytic CO2Functionalizations
Sarkar, Debotra,Weetman, Catherine,Dutta, Sayan,Schubert, Emeric,Jandl, Christian,Koley, Debasis,Inoue, Shigeyoshi
supporting information, p. 15403 - 15411 (2020/10/20)
The first acceptor-free heavier germanium analogue of an acylium ion, [RGe(O)(NHC)2]X (R = MesTer = 2,6-(2,4,6-Me3C6H2)2C6H3; NHC = IMe4 = 1,3,4,5-tetramethylimidazol-2-ylidene; X = (Cl or BArF = {(3,5-(CF3)2C6H5)4B}), was isolated by reacting [RGe(NHC)2]X with N2O. Conversion of the germa-acylium ion to the first solely donor-stabilized germanium ester [(NHC)RGe(O)(OSiPh3)] and corresponding heavier analogues ([RGe(S)(NHC)2]X and [RGe(Se)(NHC)2]X) demonstrated its classical acylium-like behavior. The polarized terminal GeO bond in the germa-acylium ion was utilized to activate CO2 and silane, with the former found to be an example of reversible activation of CO2, thus mimicking the behavior of transition metal oxides. Furthermore, its transition-metal-like nature is demonstrated as it was found to be an active catalyst in both CO2 hydrosilylation and reductive N-functionalization of amines using CO2 as the C1 source. Mechanistic studies were undertaken both experimentally and computationally, which revealed that the reaction proceeds via an N-heterocyclic carbene (NHC) siloxygermylene [(NHC)RGe(OSiHPh2)].
Betaine Catalysis for Hierarchical Reduction of CO2 with Amines and Hydrosilane To Form Formamides, Aminals, and Methylamines
Liu, Xiao-Fang,Li, Xiao-Ya,Qiao, Chang,Fu, Hong-Chen,He, Liang-Nian
, p. 7425 - 7429 (2017/06/13)
An efficient, sustainable organocatalyst, glycine betaine, was developed for the reductive functionalization of CO2 with amines and diphenylsilane. Methylamines and formamides were obtained in high yield by tuning the CO2 pressure and reaction temperature. Based on identification of the key intermediate, that is, the aminal, an alternative mechanism for methylation involving the C0 silyl acetal and aminal is proposed. Furthermore, reducing the CO2 amount afforded aminals with high yield and selectivity. Therefore, betaine catalysis affords products with a diversified energy content that is, formamides, aminals and methylamines, by hierarchical two-, four- and six-electron reduction, respectively, of CO2 coupled with C?N bond formation.
Transition metal-free methylation of amines with formaldehyde as the reductant and methyl source
Man, Nikki Y.T.,Li, Wanfang,Stewart, Scott G.,Wu, Xiao-Feng
, p. 345 - 347 (2015/11/25)
A simple transition metal-free procedure using formaldehyde for the N,N-dimethylation and N-methylation of primary and secondary anilines is reported. The reaction showed limitations on sterically hindered and electron-withdrawing anilines, but is successful on amines with electron-donating substituents. Formaldehyde acts as both the reducing agent and the carbon source in the reaction.
Iron-catalyzed reduction of CO2 into methylene: Formation of C-N, C-O, and C-C bonds
Jin, Guanghua,Werncke, C. Gunnar,Escudié, Yannick,Sabo-Etienne, Sylviane,Bontemps, Sébastien
supporting information, p. 9563 - 9566 (2015/08/18)
We report herein the use of the (dihydrido)iron catalyst, Fe(H)2(dmpe)2, for the selective reduction of CO2 into either bis(boryl)acetal or methoxyborane depending on the hydroborane used as a reductant. In a one-pot two-step procedure, the in situ generated bis(boryl)acetal was shown to be a reactive and versatile source of methylene to create new C-N but also C-O and C-C bonds.
A general catalytic methylation of amines using carbon dioxide
Li, Yuehui,Fang, Xianjie,Junge, Kathrin,Beller, Matthias
supporting information, p. 9568 - 9571 (2013/09/23)
Putting CO2 to work: Carbon dioxide is shown to be a general and selective methylating reagent for secondary and primary, aromatic and aliphatic amines under reductive conditions. A variety of tertiary amines are obtained from CO2 and commercially available silanes in high yields with good tolerance to nitrile, olefin, ether, ester, and hydroxy groups. Copyright
Process for the preparation of certain 9-substituted camptothecins
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, (2008/06/13)
A process for the preparation of water soluble camptothecin analogs, including methods for the preparation of intermediates thereof, and the compounds prepared by said process. Water soluble camptothecin analogs are prepared which may be used for inhibiting the growth of tumor cells sensitive to such analogs.
Extremely Reactive C=C Double Bonds, VI. - Tris(methylphenylamino)methane - The Chemistry of Orthoamides
Schoenberg, Alexander,Singer, Erich,Stephan, Werner
, p. 1581 - 1588 (2007/10/02)
Reactions of the title compound 2 with sulfur, selenium, thiophenol, malononitrile, 1,3-indanedione, fluorenone hydrazone, phenylmagnesium bromide, bromine, thioacetic acid, N,N'-diphenylurea, oxalyl chloride, 9,9-dichloroxanthene, phenyl isocyanate, and stilbene dibromide are described and the mechanisms are discussed.The catalytic influence of 2 on the decomposition of 9-diazofluorene in xylene and mesitylene is discussed.
