A mild and efficient protocol for the synthesis of 2,2′-difunctional biaryls from readily available benzamides and oximes by Co(OAc)2·4H2O catalysis has been developed. The catalytic cycle that includes aerobic oxidation of Co(I) to Co(III) is successfully achieved for the first time through dual-chelation-assisted C–H/C–H coupling with the assistance of catalytic Mn(acac)3. The catalytic system exhibits
Cp*-Free Cobalt-Catalyzed C–H Activation/Annulations by Traceless <i>N</i>,<i>O</i>-Bidentate Directing Group: Access to Isoquinolines
作者:Xiao-Cai Li、Cong Du、He Zhang、Jun-Long Niu、Mao-Ping Song
DOI:10.1021/acs.orglett.9b00866
日期:2019.4.19
N,O-Bidentate directing-enabled, traceless heterocycle synthesis is described via Cp*-free cobalt-catalyzedC–Hactivation/annulation. The weakly coordinating nature of the carboxylic acid was employed for the preparation of isoquinolines. Meanwhile, the N–Obond of the α-imino-oxy acid can serve as an internaloxidant. Terminal as well as internalalkynes can be efficiently applied to the catalytic
C3-Arylation of indoles with aryl ketones <i>via</i> C–C/C–H activations
作者:Zi-Qiong Guo、Hui Xu、Xing Wang、Zhen-Yu Wang、Biao Ma、Hui-Xiong Dai
DOI:10.1039/d1cc03954g
日期:——
C3-Arylation of indoles with aryl ketones is accomplished via palladium-catalyzed ligand-promoted Ar–C(O) cleavage and subsequent C–H arylation of indole. Various (hetero)aryl ketones are compatible in this reaction, affording the corresponding 3-arylindoles in moderate to good yields. Further introduction of an indole moiety into the natural products desoxyestrone and evodiamine demonstrate the synthetic
method for synthesis of oximes from aldehydes or ketones with N-hydroxyphthalimide or N-hydroxysuccinimide in water has been described. It is the first time to utilize NHPI as an oximation reagent to synthesize aldoximes and ketoximes from the corresponding organic carbonyl compounds without other reagents. The reaction tolerates various functional groups and affords the corresponding oximes in 76%–98% yields
A practical variety of o-2,3,5,6-tetrafluorobenzonitrile substituted oximes ethers bearing broad functional groups were synthesized in moderate to good yields. The key highlight of this disclosure involving a one-pot two-step tandem procedure in aqueous media: the in situ formation of aryl aldehydes or ketones oximes followed by the SNAr reaction with pentafluorobenzonitrile via the high selective