C–F Bond Cleavage Enabled Redox-Neutral [4+1] Annulation via C–H Bond Activation
作者:Cheng-Qiang Wang、Lu Ye、Chao Feng、Teck-Peng Loh
DOI:10.1021/jacs.6b12142
日期:2017.2.8
α-difluoromethylene alkyne as a nontraditional one-carbon reaction partner, a synthetically novel method for the construction of isoindolin-1-one derivatives viaRh(III)-catalyzed [4+1] annulation reaction is reported. The 2-fold C-F bondcleavage not only enables the generation of desired product under an overall oxidant-free condition but also results in a net migration of carbon-carbontriplebond. In addition
Fluorine Effects on Group Migration via a Rhodium(V) Nitrenoid Intermediate
作者:Cheng-Qiang Wang、Yu Zhang、Chao Feng
DOI:10.1002/anie.201708505
日期:2017.11.20
alkynes with N-pivaloyloxy aryl amides enabled the efficient regiospecificsynthesis of difluorinated 2-alkenyl aniline derivatives (see scheme). The fluorine substituents in the alkyne substrates diverted the course of the reaction from the conventional annulation pathway to promote the hydroarylation process involving Lossen rearrangement.
Copper-Mediated Aerobic Oxidative Trifluoromethylation of Terminal Alkynes with Me<sub>3</sub>SiCF<sub>3</sub>
作者:Lingling Chu、Feng-Ling Qing
DOI:10.1021/ja102175w
日期:2010.6.2
An efficient copper-mediated trifluoromethylation of terminalalkynes with nucleophilic trifluoromethylating reagent (Me(3)SiCF(3)) was developed. Both aromatic alkynes and aliphatic alkynes were effective, and a variety of functionalities such as amino, -OMe, -CO(2)Et, -Br, and -NO(2) were tolerated under the reaction conditions. This reaction provides a general, straightforward, and practically useful
Two practical and complementary methods are reported for the synthesis of trifluoromethylated alkynes. The first one, a mix‐and‐stir process, is based on the oxidative trifluoromethylation of readily available and bench‐stable copper acetylides while the second one, which displays a broad substrate scope and has several advantages over existing procedures, is based on the oxidativecopper‐catalyzed
Difluoromethylenephosphobetaine (Ph3P+CF2CO2−, PDFA), a known difluorocarbene reagent, was found to be able to efficiently trifluoromethylate terminalalkynes in the presence of Cu(I) and potassium fluoride. The transformation proceeded smoothly to afford the corresponding trifluoromethylated acetylenes in moderate yields.
二氟亚甲基磷酸酯(PH 3 P + CF 2 CO 2 -,PDFA),一种已知的二氟卡宾的试剂,被认为是能够在铜(I)和氟化钾的存在下有效地trifluoromethylate末端炔。转化顺利进行,以中等收率得到相应的三氟甲基化乙炔。