作者:Thibault Gendron、Raul Pereira、Hafsa Y. Abdi、Timothy H. Witney、Erik Årstad
DOI:10.1021/acs.orglett.9b04280
日期:2020.1.3
Herein, we report that iron(II)/ammonium persulfate in aqueous acetonitrile mediates the Newman-Kwart rearrangement of O-aryl carbamothioates. Electron-rich substrates react rapidly under moderate heating to afford the rearranged products in excellent yields. The mild conditions, rapid reaction rates, and suitability for scale up offers immediate practical benefits to access functionalized thiophenols
Palladium Catalyzed C–H Functionalization of <i>O</i>-Arylcarbamates: Selective <i>ortho</i>-Bromination Using NBS
作者:Alex John、Kenneth M. Nicholas
DOI:10.1021/jo300713h
日期:2012.7.6
cis-coordination of the amine. However, the amine adducts failed to undergo ortho-amination (C–N bond formation) under varied reaction conditions. Notably, the palladacycle 1d was found to react efficiently with N-iodosuccinimide (NIS) to yield the ortho-iodinated carbamate, 1e. More significantly, this reaction can be extended to a palladium-catalyzed ortho C–H bromination of aryl-O-carbamates even at 5 mol %
通过使各自的氨基甲酸酯与Pd(OAc)2在酸,CF 3 CO 2 H,CF 3 SO 3 H和p -TsOH存在下反应,合成了一系列衍生自O-苯基氨基甲酸酯的环金属化钯配合物。观察到palladacycles能配位胺和富电子的苯胺,但不能配位磺酰胺或羧酰胺。通过NMR光谱法(NOE)分析palladacycle 2b(2b · t Bu-NH 2)的t Bu-NH 2加合物显示出一种顺式-胺的配位。但是,在不同的反应条件下,胺加合物均无法进行邻氨基化(C–N键形成)。值得注意的是,发现palladacycle 1d与N-碘琥珀酰亚胺(NIS)有效反应,生成邻碘代氨基甲酸酯1e。更重要的是,即使在使用N-溴代琥珀酰亚胺(NBS)的Pd(OAc)2负载为5 mol%的情况下,该反应也可以扩展为钯催化的芳基-O-氨基甲酸酯的邻位C-H溴化反应。
Rhodium(III)-Catalyzed Sequential Cleavage of Two C–H Bonds for the Synthesis of Polyarylated Naphthols
A Rh(III)-catalyzed multiple C–H bond activation/cyclization of phenol derivatives with alkynes was developed. Polyaryl-substituted naphthol derivatives, potentially useful as organic optoelectronic materials, were obtained in moderate to good yields.
Nickel-Catalyzed Cross-Coupling of Ammonia or Primary Alkylamines with (Hetero)aryl Sulfamates, Carbamates, or Pivalates
作者:Mark Stradiotto、Preston MacQueen
DOI:10.1055/s-0036-1590819
日期:2017.8
A catalyst system capable of effecting the cross-coupling of ammonia or primary alkylamines with (hetero)arylsulfamates, carbamates, or pivalates is reported for the first time. The air-stable nickel(II) pre-catalyst C1 tolerates a broad spectrum of heterocyclic functionality within both reaction partners, as well as ether, nitrile, pyrrole, trifluoromethyl, and boronate ester substituents. In the
首次报道了能够实现氨或伯烷基胺与(杂)芳基氨基磺酸酯、氨基甲酸酯或新戊酸酯交叉偶联的催化剂体系。空气稳定的镍 (II) 预催化剂 C1 可耐受两种反应伙伴以及醚、腈、吡咯、三氟甲基和硼酸酯取代基中的广谱杂环官能团。在涉及伯烷基胺和(杂)芳基氨基磺酸酯和氨基甲酸酯的反应的情况下,实现了室温交叉偶联。
Mixing <i>O</i>-Containing and <i>N</i>-Containing Directing Groups for C–H Activation: A Strategy for the Synthesis of Highly Functionalized 2,2′-Biaryls
N-containing directing groups has been developed for the synthesis of 2,2′-biaryl via Pd-mediated C–Hbond activation and oxidative coupling. This new transformation may proceed through a mechanism involving Pd(II) and Pd(IV) intermediates. We found the use of PTSA and HFIP to be critical for the reaction and suggest that these reagents could serve as efficient ligands for this C–Cbond formation. This