27126-13-2Relevant academic research and scientific papers
Palladium-Catalyzed Diarylation of Isocyanides with Tetraarylleads for the Selective Synthesis of Imines and α-Diimines
Tran, Cong Chi,Kawaguchi, Shin-Ichi,Kobiki, Yohsuke,Matsubara, Hitomi,Tran, Dat Phuc,Kodama, Shintaro,Nomoto, Akihiro,Ogawa, Akiya
, p. 11741 - 11751 (2019/10/02)
Using tetraaryllead compounds (PbAr4) as arylating reagents, isocyanides undergo selective diarylation in the presence of palladium catalysts such as Pd(OAc)2 or Pd(PPh3)4 to afford imines and/or α-diimines based on the isocyanide employed. With aliphatic isocyanides, imines are obtained preferentially, whereas α-diimines are formed in the case of electron-rich aromatic isocyanides. The differences in imine/α-diimine selectivity can be attributed to the stability of imidoylpalladium intermediates formed in this catalytic reaction. Compared with other arylating reagents, tetraaryllead compounds are excellent candidates for use in the selective transformations to imines and/or α-diimines, especially in terms of inhibiting the oligomerization of isocyanides, which results in a lower product selectivity in many transition-metal-catalyzed reactions of isocyanides.
Palladium-Catalyzed Synthesis of α-Diimines from Triarylbismuthines and Isocyanides
Kobiki, Yohsuke,Kawaguchi, Shin-Ichi,Ogawa, Akiya
, p. 3490 - 3493 (2015/07/28)
In this study, we report a highly selective coupling reaction between triarylbismuthines and isocyanides using palladium diacetate as the catalyst, affording α-diimines, with the formation of three C-C bonds. Among several aryl sources (Ar-YLn: Y = B, Sn, Pb, Sb, Bi, I), only triarylbismuthines successfully undergo coupling with isocyanides to selectively afford α-diimines. The coupling reaction exhibits the advantages of high atom economy and convenient operation, with no need for any additive.
Radical amination with trimethylstannylated benzophenone imine
Lamas, Marie-Celine,Vaillard, Santiago E.,Wibbeling, Birgit,Studer, Armido
supporting information; experimental part, p. 2072 - 2075 (2010/07/07)
Figure presented Intermolecular radical amination reactions of various primary, secondary, and tertiary alkyl radicals by using trimethylstannylated benzophenone imine A as a novel radical acceptor to provide imines of type B are described. These imines are readily reduced with NaBH4 to the corresponding secondary amines C. The novel radical amination can be combined with typical radical cyclization reactions.
Reactions of lithium hydridosilylamides with carbonyl compounds and mixtures of carbonyl compounds and chlorotrimethylsilane
Schneider, Jan,Popowski, Eckhard,Fuhrmann, Hans
, p. 663 - 672 (2007/10/03)
The lithium hydridosilylamides Me2(H)SiN(Li)R (1: R = CMe3, 2: R = SiMe3) were allowed to react either with the non-enolizable carbonyl compounds CH2=C(Me)CHO, PhCHO and Ph2CO followed by trapping with chlorotrimethylsilane (A), or with mixtures of these carbonyl compounds and chlorotrimethylsilane (B). In the second case the course of the reactions is determined by the carbonyl compound. The composition of the reaction mixtures is nearly the same according to A and B. Main products in the reactions with the aldehydes are the corresponding imines R1CH=NR R1 = CH2=C(Me), Ph) 3, 4, 8, 9 formed by addition of the hydridosilylamides to the C=O group of the aldehydes and subsequent LiOSiMe2H elimination. Partial hydrosilylation of the aldehydes by the hydridosilanolate followed by the trimethylsilylation yields the alkoxydisiloxanes R1CH2OSiMe2OSiMe3 6, 11. In some cases 2 partially reacts under hydrosilylation to give the alkoxydisilazanes R1CH2OSiMe2NHSiMe3 7, 12. The hydrosilylation is the preferred reaction of 1 and 2 with benzophenone. The compounds Ph2CHOSiMe2NHR 13, 14 are obtained. This difference in the reaction behaviour of 1 and 2 towards the aldehydes and benzophenone is mainly due to steric reasons. Depending on the conditions the imines Ph2C=NR 20, 21 may be formed. Ph2CHOSiMe2OSiMe3 (22) is a secondary product of imine formation. In all reactions of 1 and 2 with the carbonyl compounds the corresponding alkoxysilanes R1CH2OSiMe3 (5: R1 = CH2=C(Me), 6: R1 = Ph) and Ph2CHOSiMe3 (15) are generated. Compounds resulting from a reaction of 1 and 2 with chlorotrimethylsilane are produced to minor extent, but only if the molar ratio of amide to carbonyl compounds is not greater than one. The formation of a silanimine intermediate in reaction according to B is not observed.
Electron Paramagnetic Resonance Study of Imine Radical Cations in Low-temperature Solid Matrices
Rhodes, Christopher J.,Agirbas, Hikmet
, p. 3303 - 3308 (2007/10/02)
A series of imine radical cations has been studied by EPR spectroscopy, generated in low-temperature halogenocarbon matrices by γ-radiolysis.Radicals of the type ArCH=NR.+ tend to be formed in the 2A'state, corresponding to ionisation of the in-plane (mainly the nitrogen lone-pair) a' orbital (I).These are isostructural with the corresponding vinyl radicals and show angular geometries at the radical centres and large couplings (ca. 85 G) to the proton trans to the nominally nitrogen-localised SOMO (I).When R = But, a 12 G long-range coupling is observed to a single proton from the But group, arising via the W-configuration (II).This coupling was found to persist in the CFCl3 matrix up to its melting point (ca. 160 K), but was lost reversibly in the higher melting CCl4 matrix at ca. 200 K. When R = phenyl, the radical centre is rendered linear, because of the partial ?-bonding between the aromatic ring and the nitrogen atom due to delocalisation of the unpaired electron, as shown by a fall in the parallel (14N) coupling with a concomitant increase in the nitrogen 2p/2s ratio, and by the observation of couplings to the ortho and para phenyl protons. For imines derived from benzophenone (Ph2C=NR) the tendency is for ionisation to occur from the ?-orbital (III) which has large spin densities on the para carbon atoms. Benzophenone imine (Ph2C=NH), in addition to forming the ?-state (III), was found to deprotonate, giving rise to the Ph2C=N. radical.Similar behaviour was shown by benzophenone oxime, which gave only the corresponding iminoxyl radical (Ph2C=N-O.), and we propose that this is due to the dissolution of the latter two materials in the form of hydrogen-bonded molecular clusters in the non-polar freon solvent, thus facilitating deprotonation of the primary cations.
