Rhodium-Catalyzed C–H Activation of Phenacyl Ammonium Salts Assisted by an Oxidizing C–N Bond: A Combination of Experimental and Theoretical Studies
作者:Songjie Yu、Song Liu、Yu Lan、Boshun Wan、Xingwei Li
DOI:10.1021/ja511796h
日期:2015.2.4
and the coupling with unactivated alkenes such as styrenes and aliphatic olefins gave ortho-olefinated acetophenoes. In both systems the reactions proceeded with a broad scope, high efficiency, and functional group tolerance. Moreover, efficient one-potcoupling of diazo esters has been realized starting from α-bromoacetophenones and triethylamine. The reaction mechanism for the coupling with diazo
由氧化导向基团辅助的 Rh(III) 催化的 CH 活化已演变为用于构建杂环的温和且氧化还原经济的策略。尽管取得了成功,但这些偶联系统目前仅限于裂解氧化性 NO 或 NN 键。允许互补碳环合成的氧化性 CN 键的断裂是前所未有的。在本文中,具有氧化性 CN 键的 α-铵苯乙酮被设计为在氧化还原中性条件下 Rh(III) 催化 CH 活化的底物。与α-重氮酯偶联得到苯并环戊酮,与未活化烯烃如苯乙烯和脂肪族烯烃偶联得到邻位烯化苯乙酮。在这两个系统中,反应都以广泛的范围、高效率和官能团耐受性进行。而且,从α-溴苯乙酮和三乙胺开始,已经实现了重氮酯的有效一锅偶联。通过实验和理论相结合的方法研究了与重氮酯偶联的反应机理。特别是,DFT 研究仔细检查了三种不同的机制途径,这表明 CH 活化是通过 C 键合烯醇化物辅助的协同金属化-去质子化机制发生的,并且是限速的。在随后的 CC 形成步骤中,最低能量途
Stereoselective Synthesis of<b>
<i>trans</i>
</b>-β-Substituted γ-Ferrocenyl-γ-butyrolactones via Ammonium Ylides
作者:Yongmin Liang、Ling Shi、Yao Han、Zhanjun Yang、Weimin Liu
DOI:10.1055/s-2005-872143
日期:——
trans-P-substituted gamma-ferrocenyl-gamma-butyrolactones were prepared via the reaction of quaternaryammoniumsalts with electron-deficient trisubstituted alkene 1 under the optimum conditions. Moderate to good yields and excellent trans stereoselectivity) were achieved for the new compounds 2-10. The X-ray crystal structure of 2a was determined and all the products were characterized by H-1 NMR
A Novel Facile Synthetic Route to Highly Substituted 2,3-Dihydrofurans via Ammonium Ylides
作者:Yongmin Liang、Zhanjun Yang、Mingjin Fan、Weimin Liu
DOI:10.1055/s-2005-869956
日期:——
Tetrasubstituted 2,3-dihydrofurans derivatives were prepared via the reaction of quaternary ammonium salts 1 with electrophilic alkenes 2 in the presence of powered K2CO3, usually in a stereoselective manner with good to high yields. The stereochemistry of dihydrofurans was secured by NMR signals and subsequently confirmed by X-ray diffraction.
The first example of ring expansion of N-tosylaziridines to 2-aroyl-N-tosylazetidines with nitrogen ylides in an aqueous medium
作者:Garima、Vishnu P. Srivastava、Lal Dhar S. Yadav
DOI:10.1039/c004736h
日期:——
Tertiary amine catalyzed ring expansion reaction of N-tosylaziridines to 2-aroyl-N-tosylazetidines, with nitrogen ylides formed in situ from phenacyl bromide derivatives in a silica gel-water system is reported. The reaction expeditiously affords functionalized azetidines in high yields and stereoselectivities in a one-pot process. Advantageously, the protocol precludes the preparation and isolation
Substrates, systems, and methods for array synthesis and biomolecular analysis
申请人:Vibrant Holdings, LLC
公开号:US10286376B2
公开(公告)日:2019-05-14
Disclosed herein are formulations, substrates, and arrays. In certain embodiments, substrates and arrays comprise a porous layer for synthesis and attachment of polymers or biomolecules. Also disclosed herein are methods for manufacturing and using the formulations, substrates, and arrays, including porous arrays. Also disclosed herein are formulations and methods for one-step coupling, e.g., for synthesis of peptides in an N->C orientation. In some embodiments, disclosed herein are formulations and methods for high efficiency coupling of biomolecules to a substrate.