14856-79-2Relevant articles and documents
Convergent Synthesis of Pyrrolidines, Piperidines, Perhydroazepines and Tetrahydroisoquinolines via Zirconocene η2-Imine Complexes
Harris, Michael C. J.,Whitby, Richard J.,Blagg, Julian
, p. 4287 - 4290 (1995)
Zirconocene η2-imine complexes formed by a C-H activation route from a variety of amines are trapped by ω-halo-alkenes or -alkynes to afford 2,3-disubstituted pyrrolidines, piperidines and perhydroazepines on work up and cyclisation.In some cas
Latent Nucleophilic Carbenes
Marchenko, Anatoliy,Koidan, Georgyi,Hurieva, Anastasiya,Shvydenko, Kostiantyn,Rozhenko, Alexander B.,Rusanov, Eduard B.,Kyrylchuk, Andrii A.,Kostyuk, Aleksandr
, p. 373 - 385 (2021/12/27)
Using DFT and ab initio calculations, we demonstrate that noncyclic formamidines can undergo thermal rearrangement into their isomeric aminocarbenes under rather mild conditions. We synthesized the silylformamidine, for which the lowest activation energy in this process was predicted. Experimental studies proved it to serve as a very reactive nucleophilic carbene. The reactions with acetylenes, benzenes, and trifluoromethane proceeded via insertion into sp, sp2, and spCH bonds. The carbene also reacted with the functional groups, such as CHO, COR, and CN at double or triple bonds, displaying high mobility of the trimethylsilyl group. The obtained silylformamidine can be considered as a latent nucleophilic carbene. It can be prepared in bulk quantities, stored, and used when the need arises. Calculation results predict similar behavior for some other silylated formamidines and related compounds.
Formation of Aromatic O-Silylcarbamates from Aminosilanes and Their Subsequent Thermal Decomposition with Formation of Isocyanates
Gründler, Franziska,Herbig, Marcus,Kroke, Edwin,Scholz, Henrik,Schwarzer, Sandra,Wagler, J?rg
, p. 2211 - 2224 (2021/06/11)
A novel phosgene-free route to different isocyanates starts from CO2 and aminosilanes (cf. silylamines) to form so-called carbamoyloxysilanes (O-silylcarbamates), i. e., compounds with the general motif R1R2N?CO?O?SiR3R4R5 as potential precursors. We focused on the insertion reaction of CO2 into Si?N bonds of substrates with cyclic (mostly aromatic) amine substituents, i. e., PhNHSiMe3, (PhNH)2SiMe2, PhCH2NHSiMe3, p-(MeO)C6H4NHSiMe3, o-C6H4(NHSiMe3)2, 1,2-C6H10(NHSiMe3)2, o-C6H4(NHSiMe3)(CH2NHSiMe3) and 1,8-C10H6(NHSiMe3)2. Compared to previously investigated aminosilanes these reactions are hindered due to the reduced nucleophilicity/basicity of the N-atoms. Whereas slightly increased CO2 pressure (8 bar) and prolonged reaction times (24 h) were sufficient to overcome hindrance of the insertion into, e. g., PhNHSiMe3, intermolecular effects in some two-fold NHSiMe3 functionalized substrates led to partial mono-insertion (e. g., into o-C6H4(NHSiMe3)(CH2NHSiMe3)) or intra-molecular condensation of the intermediate insertion product in case of 1,8-C10H6(NHSiMe3)2 to form 1H-perimidin-2(3H)-one and other side products. Thermal treatment of mono-silylated O-silylcarbamates RHN?CO?O?SiR’3 resulted mainly in the formation of substituted ureas (RHN)2CO, whereas desired isocyanates could not be detected in these cases. Therefore, we continued our studies focussing on N,O-bissilylated precursors, which were obtained by an additional N-silylation of the O-silylated carbamates. This allowed the successful formation of isocyanates. As a sole byproduct hexamethyldisiloxane is formed. In all cases, known as well as yet unknown substances were characterised by 1H, 13C and 29Si NMR spectroscopy, along with X-ray diffraction analysis for crystallized solids.
Zirconium Hydroaminoalkylation. An Alternative Disconnection for the Catalytic Synthesis of α-Arylated Primary Amines
Koperniku, Ana,Foth, Paul J.,Sammis, Glenn M.,Schafer, Laurel L.
supporting information, p. 18944 - 18948 (2019/12/04)
Primary amine products have been prepared using zirconium-catalyzed hydroaminoalkylation of alkenes with N-silylated benzylamine substrates. Catalysis using commercially available Zr(NMe2)4 affords an alternative disconnection to acc
