The first example of photoredox strategy for synthesis of phenanthrene skeletons through C(sp3)–H functionalization under external oxidant-free conditions is achieved. This transformation relies on the keto–enol tautomerism of 1,3 dicarbonyl moiety, i.e., the enol form of 1,3-dicarbonyl derivatives with relatively lower oxidation potential can be activated by the excited acridinium photocatalyst. The
Cobalt-Catalyzed Cross-Coupling Reactions of Heterocyclic Chlorides with Arylmagnesium Halides and of Polyfunctionalized Arylcopper Reagents with Aryl Bromides, Chlorides, Fluorides and Tosylates
A range of aromatic organocopper or organomagnesium compounds undergo smooth cross-coupling reactions with aryl bromides, chlorides, fluorides and tosylates, leading to polyfunctionalized aromatics or heterocycles in the presence of cobalt salts (5-7.5 mol%) as catalysts. Very mild reaction conditions are needed and, in the case of cross-coupling with organocopper compounds, Bu4NI (1 equiv) and 4-fluorostyrene (20 mol%) are essential as promoters for successful couplings.
<i>N</i>-Bromosuccinimide-Induced C–H Bond Functionalization: An Intramolecular Cycloaromatization of Electron Withdrawing Group Substituted 1-Biphenyl-2-ylethanone for the Synthesis of 10-Phenanthrenol
作者:Ya-Ting Jiang、Zhen-Zhen Yu、Ya-Kai Zhang、Bin Wang
DOI:10.1021/acs.orglett.8b01160
日期:2018.7.6
intramolecular cycloaromatization for the synthesis of 10-phenanthrenols from electron-withdrawing groupsubstituted 1-biphenyl-2-ylethanones is described. The in situ generated bromide was designed to act as an initiator for the radical C–H bond activation. An oxidative cross-dehydrogenative coupling reaction of a highly active C–H bond with an inert C–H bond readily occurs under mild conditions without
Using a catalytic amount of N-iodosuccinimide (NIS) in combination with O2 in air, an aerobic oxidative reaction was carried out to efficiently and scalably construct a series of 10-phenanthrenols under sunlight at room temperature. Mechanistic studies reveal that H2O2 generated in situ was responsible for the conversion of I2 to IOH as a potential initiator for later catalytic cycle.
使用催化量的N-碘代琥珀酰亚胺 (NIS) 与空气中的O 2结合,进行有氧氧化反应,以在室温下在阳光下有效且可扩展地构建一系列 10-菲酚。机理研究表明,原位产生的H 2 O 2负责将 I 2转化为 IOH,作为后期催化循环的潜在引发剂。
Pd(II) complexes of Schiff bases and their application as catalysts in Mizoroki-Heck and Suzuki-Miyaura cross-coupling reactions