212-74-8Relevant articles and documents
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.].
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.
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.
