212-74-8Relevant academic research and scientific papers
Fine-tuning hydroxylamines as single-nitrogen sources for Pd(0)-catalyzed diamination of o-bromo(or chloro)-biaryls
Bai, Jiaxing,Ding, Pin,Han, Lingbo,Liu, Jingjing,Luan, Xinjun
, (2022/03/19)
Transition metal-catalyzed diamination by hydroxylamines is a common approach for making three-membered aziridines, while its use for building the larger N-heterocycles is still underdeveloped. Herein, we report an efficient Pd(0)-catalyzed inter-molecular [4+1] annulation of o-bromo(or chloro)-biaryls with bifunctional secondary hydroxylamines for the one-step assembly of synthetically useful carbazoles. Noteworthily, a linchpin for this domino reaction was the judicious selection of both the amino-sources and Pd(0)-catalysts for enabling the prerequisite oxidative addition of aryl halides to Pd(0)-species in the presence of hydroxylamines with a labile N-O bond. [Figure not available: see fulltext.].
An Approach to Tetraphenylenes via Pd-Catalyzed C-H Functionalization
Jiang, Hang,Zhang, Yu,Chen, Dushen,Zhou, Bo,Zhang, Yanghui
, p. 2032 - 2035 (2016/06/01)
Tetraphenylenes not only are theoretically and experimentally interesting but also have potential applications in a variety of fields such as materials science, supramolecular chemistry, and asymmetric catalysis. A facile and efficient approach is reported for the syntheis of tetraphenylene and its derivatives from 2-iodobiphenyls via Pd-catalyzed C-H activation. A range of substituted tetraphenylenes can be synthesized using this method, and the reaction can be performed on gram scale with relatively high efficiency, demonstrating its practical utility. This novel approach provides easy access to tetraphenylenes and should facilitate research on the application of this type of fascinating molecules.
Synthesis of biphenylenes and tetraphenylenes using copper-catalyzed coupling of arylzinc intermediates
Kabir, S.M. Humayun,Hasegawa, Masashi,Kuwatani, Yoshiyuki,Yoshida, Masato,Matsuyama, Haruo,Iyoda, Masahiko
, p. 159 - 165 (2007/10/03)
Biphenylene and some of its 2,3,6,7- and 1,8-substituted derivatives were synthesized using the CuCl2-mediated intramolecular coupling of an organozinc species prepared from 2,2′-dilithiobiaryls with one or two molar equiv. of ZnCl2 or ZnBr2 in THF. Although most of the reactions of 2,2′-dilithiobiaryls with CuCl2 in THF in the absence of ZnCl2 or ZnBr2 led to biphenylenes as a major product, similar reactions of the organozinc species with CuCl2 in THF produced biphenylenes in much better yields, due to smooth transmetallation and reductive elimination reactions. In particular, the copper-mediated cyclization of benzannelated organozinc intermediates, prepared from equimolar proportions of 2,2′-dilithiobiaryls with ZnCl2, proceeded smoothly and selectively to afford the desired biphenylenes in 46-81% yield except for the reaction of the zinc intermediate derived from 4,4′,5,5′-tetramethoxy-2,2′-dilithiobiphenyl with ZnCl2 (1.0 molar equiv.). The reaction of the tetramethoxy-substituted organozinc species with CuCl2 produced 2,3,6,7,10,11,14,15-octamethoxytetraphenylene as a major product in 67% yield.
Novel synthesis of biphenylene and its derivatives using intramolecular coupling of zincacyclopentadienes
Iyoda, Masahiko,Kabir, S. M. Humayun,Vorasingha, Anusorn,Kuwatani, Yoshiyuki,Yoshida, Masato
, p. 5393 - 5396 (2007/10/03)
Biphenylene and its derivatives were synthesized using the intramolecular coupling of benzoannelated zincacyclopentadiene intermediates prepared from 2,2'-dilithiobiaryls with ZnCl2. The reaction proceeded smoothly and selectively to give the desired biphenylenes in moderate to good yields.
ORGANOSILICON HETEROCYCLIC COMPOUNDS. LX. UNSATURATED SILICON-OXYGEN-CONTAINING COMPOUNDS: POTENTIAL SOURCES OF DICHLOROSILANONE
Chernyshev, E. A.,Krasnova, T. L.,Mudrova, N. A.,Bochkarev, V. N.
, p. 1502 - 1509 (2007/10/02)
The thermolysis of a number of unsaturated heterocyclic compounds containing the endocyclic grouping -OSiCl2- is accompanied by the intermediate formation of dichlorosilanone.The introduction of trichlorosilane into the zone of the pyrolysis of these compounds leads to a considerable increase in the extent of their conversion, and the latter is not only an acceptor of dichlorosilanone, for it reacts with intermediate hydrocarbon diradicals.Is is concluded that the process of the thermal breackdown of the compounds studied with the elimination of the intermediate dichlorosilanone is reversible.
New Method for the Preparation of Activated Nickel and Cobalt Powders and Their Application in Biaryl Synthesis
Chao, C. S.,Cheng, C. H.,Chang, C. T.
, p. 4904 - 4907 (2007/10/02)
An activated nickel powder has been prepared by the procedure of electrolysis of a NiSO4 aqueous solution with Hg as the cathode to form a nickel amalgam followed by the removal of the mercury from the amalgam at 150 deg C and 10-3 torr.The nickel powder, similar to Cu in Ullmann's biaryl synthesis, has been found to react with aryl iodide and aryl bromide at 140 deg C to give biaryls in good yields and with dibrombenzene to yield a number of interesting products including triphenylene, tetraphenylene, and polyphenyls, depending on the relative position of the dibromo groups.In the presence of KI, the powder also induces, unprecedentedly, the homo coupling of an aryl chloride to a biaryl.The activity of the activated nickel powder was further demonstrated by the reaction with benzyl bromide to give 1,2-diphenylethane and with α,α-dichlorotoluene to afford mainly trans-stilbene.
BIPHENYLENES AND HETEROCYCLIC ANALOGUES OF BIPHENYLENE. PART I. PREPARATION OF BIPHENYLENE AND OCTACHLOROBIPHENYLENE BY VACUUM PYROLYSIS OF BENZO(c)CINNOLINES; PYROLYSIS OF BENZOCINNOLINE N-OXIDE.
Kanoktanaporn, Santhi,MacBride, J. A. Hugh
, p. 2901 - 2910 (2007/10/02)
Vacuum sublimation of benzocinnolines through a silica tube at 700-950 deg C gives biphenylenes in good yield.The first reaction when benzocinnoline N-oxide is similarly pyrolysed is deoxygenation to benzocinnoline.
