Pd(II)-Catalyzed ortho-C–H Oxidation of Arylacetic Acid Derivatives: Synthesis of Benzofuranones
摘要:
Pd(II)-catalyzed ortho-C-H acetoxylation of arylacetic acid derivatives is demonstrated with the aid of a novel S-methyl-S-2-pyridylsulfoximine (MPyS) directing group (DG). The alpha-mono- and alpha-unsubstituted arylacetic acid derivatives were readily employed in the ortho-C-H acetoxylations. The oxidation products are hydrolyzed, and the MPyS-DG is easily recovered, providing ready access to 0-hydroxyarylacetic acids. 3-Mono- and 3-unsubstituted benzofuranones are synthesized from 0-hydroxyarylacetic acids.
Flash Photolytic Generation of Primary, Secondary, and Tertiary Ynamines in Aqueous Solution and Study of Their Carbon-Protonation Reactions in That Medium
作者:Y. Chiang、A. S. Grant、A. J. Kresge、S. W. Paine
DOI:10.1021/ja9601797
日期:1996.1.1
secondary ynamines. Solvent isotope effects and the form of acid−base catalysis show that the acid-catalyzed path involves formation of keteniminium ions by rate-determining proton transfer to the β-carbon atoms of the ynamines. The ions generated from primary and secondary ynamines then lose nitrogen-bound protons to give ketenimines, and the ketenimines obtained from secondary ynamines are hydrated
Selective radical amination of aldehydic C(sp<sup>2</sup>)–H bonds with fluoroaryl azides via Co(<scp>ii</scp>)-based metalloradical catalysis: synthesis of N-fluoroaryl amides from aldehydes under neutral and nonoxidative conditions
作者:Li-Mei Jin、Hongjian Lu、Yuan Cui、Christopher L. Lizardi、Thiago N. Arzua、Lukasz Wojtas、Xin Cui、X. Peter Zhang
DOI:10.1039/c4sc00697f
日期:——
proven to be an effective metalloradical catalyst for intermolecularamination of C(sp2)–H bonds of aldehydes with fluoroaryl azides. The [Co(P1)]-catalyzed process can employ aldehydes as the limiting reagents and operate under neutral and nonoxidative conditions, generating nitrogen gas as the only byproduct. The metalloradical aldehydic C–H amination is suitable for different combinations of aldehydes
D 2h对称酰胺卟啉 3,5-Di t Bu-IbuPhyrin [Co( P1 )]的 Co( II ) 配合物已被证明是一种有效的金属基催化剂,用于 C(sp 2 )–H 键的分子间胺化醛与氟芳基叠氮化物。[Co( P1 )]-催化过程可以使用醛作为限制试剂并在中性和非氧化条件下运行,产生氮气作为唯一的副产品。金属基醛 C-H 胺化适用于醛和氟芳基叠氮化物的不同组合,产生相应的N-氟芳基酰胺的产率非常好。一系列机理研究支持 Co( II ) 催化的分子间 C-H 胺化的逐步自由基机制。
Identifying the potential of pulsed LED irradiation in synthesis: copper-photocatalysed C–F functionalisation
作者:Thomas P. Nicholls、Johnathon C. Robertson、Michael G. Gardiner、Alex C. Bissember
DOI:10.1039/c8cc02244e
日期:——
It has been reported that pulsedirradiation can improve photosynthetic activity and phytochemical production in plants. Intrigued and inspired by these observations, we postulated that pulsedirradiation strategies may have broader implications in organic synthesis. We report here the results of a proof-of-concept study demonstrating that pulsedLEDirradiation enhances the efficiency of a visible
(Diacetoxyiodo)benzene-Mediated Oxygenation of Benzylic C(sp<sup>3</sup>)-H Bonds with<i>N</i>-Hydroxyamides at Room Temperature
作者:Peng-Cheng Qian、Yu Liu、Ren-Jie Song、Ming Hu、Xu-Heng Yang、Jian-Nan Xiang、Jin-Heng Li
DOI:10.1002/ejoc.201403616
日期:2015.3
A new, metal-free method for the formation of C(sp3)–O bonds was established by PhI(OAc)2-mediated oxygenation of benzylicC(sp3)–H bonds with N-hydroxyamides at roomtemperature, in which the C(sp3)–H oxidation is activated by a polyflurophenylamide group.