We have developed a copper/manganese-mediated oxidative rearrangement of benzylamines to 4H-3,1-benzoxazines of potent interest in medicinal applications. The reaction proceeds uniquely through the initial copper/manganese-promoted intramolecular C-H amination giving benzazetidine intermediates and subsequent 4n electrocyclic ring opening/6 pi electrocyclic ring closing cascade. The key to success is the introduction of picolinamide-based N,N-bidentate directing group. The obtained benzoxazines can also be readily hydrolyzed to the corresponding 2-aminobenzyl alcohols, thus indicating that the overall transformations is regarded as the ortho-aminative rearrangement of benzylarnines to benzylic alcohols.
作者:Son H. Doan、Mohanad A. Hussein、Thanh Vinh Nguyen
DOI:10.1039/d1cc02947a
日期:——
used to be one of the most powerful synthetic tools to functionalize alcohols and nitriles, providing valuable N-alkyl amide products. However, this reaction has not been frequently used in modern organicsynthesis due to its employment of strongly acidic and harsh reaction conditions, which often lead to complicated side reactions. Herein, we report the development of a new method using salts of the
Cobalt-Catalyzed, Aminoquinoline-Directed C(sp<sup>2</sup>)H Bond Alkenylation by Alkynes
作者:Liene Grigorjeva、Olafs Daugulis
DOI:10.1002/anie.201404579
日期:2014.9.15
A method for cobalt‐catalyzed, aminoquinoline‐ and picolinamide‐directed C(sp2)Hbondalkenylation by alkynes was developed. The method shows excellent functional‐group tolerance and both internal and terminal alkynes are competent substrates for the coupling. The reaction employs a Co(OAc)2⋅4 H2O catalyst, Mn(OAc)2 co‐catalyst, and oxygen (from air) as a terminal oxidant.
开发了一种钴催化、氨基喹啉和吡啶酰胺引导的炔烃 C(sp 2 ) H 键烯基化方法。该方法显示出优异的官能团耐受性,内部和末端炔烃都是偶联的有效底物。该反应采用Co(OAc) 2 ⋅4 H 2 O催化剂、Mn(OAc) 2助催化剂和氧气(来自空气)作为终端氧化剂。
Oxidative C–H/N–H Annulation of Aromatic Amides with Dialkyl Malonates: Access to Isoindolinones and Dihydrobenzoindoles
A copper-mediated oxidative C–H/N–H annulation of aromatic amides with dialkyl malonates has been presented to afford synthetically valuable dihydrobenzoindoles and isoindolinones. The reaction proceeds through direct oxidative C(sp2)–H/C(sp3)–H coupling followed by an intramolecular N–H/C(sp3)–H dehydrogenative coupling to deliver the target motifs with broad scope and functional group tolerance.
A cobalt(II)-catalyzed regioselective aryl C–H bond oxygenation between arenes and aryl or aliphatic carboxylic acids under bidendate-chelation assistance is developed. This method provides an efficient approach to acyoxy-substituted arenes with a broad range of functional group tolerance. Furthermore, this reaction system could be further applied to the preparation of polyfunctional naphthylenes.
Highly Efficient Method for the Synthesis of Carboxamides from Carboxylic Acids and Amines Using Pyridine-3-sulfonyl Chloride (3-PSC)
作者:Setsuo Funasaka、Koji Kato、Teruaki Mukaiyama
DOI:10.1246/cl.2008.506
日期:2008.5.5
The use of pyridine-3-sulfonyl chloride (3-PSC) in dehydrating condensation was investigated. This novel reagent was successfully employed as a mild dehydrating reagent for preparing various carboxamides in good to excellent yields from the corresponding carboxylic acids and amines.