Weakly Coordinating <i>tert</i>-Amide-Assisted Ru(II)-Catalyzed Synthesis of Azacoumestans via Migratory Insertion of Quinoid Carbene: Application in the Total Synthesis of Isolamellarins
作者:Souradip Sarkar、Rajarshi Samanta
DOI:10.1021/acs.orglett.2c01556
日期:2022.7.1
A weakly coordinating tert-amide-directed straightforward method was developed for the synthesis of azacoumestans using the corresponding azaheterocycle derivatives and diazonaphthoquinones under cheap Ru(II)-catalyzed conditions. The reaction proceeds via migratory insertion of quinoid carbene and subsequent Brønstead acid-mediated cyclization. The optimized C2-selective method offered a wide scope
开发了一种弱配位叔酰胺定向的直接方法,用于在廉价的 Ru(II) 催化条件下使用相应的氮杂杂环衍生物和重氮萘醌合成氮杂香豆素。该反应通过醌型卡宾的迁移插入和随后的布朗斯特酸介导的环化进行。优化的 C2 选择性方法提供了广泛的重要氮杂杂环化合物。通过开发的方案合成了生物活性天然产物,如异醇 A 和 B。初步机制研究强调了可能的机制途径。
A para- to meta-isomerization of phenols
作者:Simon Edelmann、Jean-Philip Lumb
DOI:10.1038/s41557-024-01512-1
日期:——
Their properties are intimately linked to the relative substitution pattern of the aromaticring, reflecting well-known electronic effects of the OH group. Because of these ortho-, para-directing effects, meta-substituted phenols have historically been more difficult to synthesize. Here we describe a procedure to transpose phenols that hinges on a regioselective diazotization of the corresponding ortho-quinone
Rhodium-catalyzed synthesis of a C(3) disubstituted oxindole: an approach to diazonamide A
作者:Takayuki Sawada、Douglas E. Fuerst、John L. Wood
DOI:10.1016/s0040-4039(03)01038-4
日期:2003.6
A two step synthesis of a C(3) disubstituted oxindoles via the rhodium(II)-catalyzed coupling of diazoketone (6) and 3-methyloxindole (9) is reported. (C) 2003 Elsevier Science Ltd. All rights reserved.
Evidence against 1,2-migrations in aryl cations
作者:Paul Haberfield、Claudia Cardona、Mark Bell
DOI:10.1021/jo00175a014
日期:1984.1
Synthesis of Diazoquinones and Azidophenols via Diazo‐Transfer Reaction of Phenols
An efficient diazo-transfer reaction of phenol is described. o-Quinone diazide (diazoquione) were synthesized from phenol by the diazo-transfer reaction using 2-azido-1,3-bis(2,6-diisopropylphenyl)imidazolium hexafluorophosphate (IPrAP), which is safe and stable crystalline, in MeOH in the presence of iPr2NH or DMAP. In addition, diazoquinones reacted with sodium azide smoothly in 2-methoxyethanol