Synthesis of Novel 1,3,5-Tris(arylazo)benzenes via Pd-Catalyzed Couplings and Cu(I)-Mediated Direct Oxidations
摘要:
A series of novel 1,3,5-tris-azobenzenes were prepared from 1,3,5-trihalobenzene via Pd-catalyzed couplings of N-Boc aryl hydrazines and subsequent Cu(I)-mediated direct oxidations. The oxidation of tris-arylhydrazide provided the azobenzene as a mixture of all four of the possible E/Z-isomers; [E,E,E]-, [E,E,Z]-, [E,Z,Z]-, and [Z,Z,Z]-1,3,5-tris-azobenzenes. A slow removal of the solvent in the dark transformed the isomers into the all-trans, [E,E,E]-isomer.
Regioselective synthesis of aryl hydrazides by palladium-catalyzed coupling of t-butylcarbazate with substituted aryl bromides
摘要:
Substituted aryl bromides are coupled with t-butylcarbazate in the presence of a palladium catalyst and base to afford regioselectively, the corresponding amidation product or amination product depending upon the position of the substituents on the aryl bromide. (C) 1999 Elsevier Science Ltd. All rights reserved.
Expedient synthesis of indoles from N-Boc arylhydrazines
作者:Young-Kwan Lim、Cheon-Gyu Cho
DOI:10.1016/j.tetlet.2004.01.011
日期:2004.2
The readily available N-Boc arylhydrazines undergo efficient Fischer cyclizations to provide the indoles in good yields, when reacted with enolizable ketones.