Exploration of Biaryl Carboxylic Acids as Proton Shuttles for the Selective Functionalization of Indole C–H Bonds
摘要:
A survey of diversely substituted 2-arylbenzoic acids were synthesized and tested for use as proton shuttle in the direct arylation of indoles with bromobenzenes. It was found that 3-ethoxy-2-phenylbenzoic acid gives superior yield and selectivity for this class of substrates.
Mild and selective base-free C–H arylation of heteroarenes: experiment and computation
作者:Hannes P. L. Gemoets、Indrek Kalvet、Alexander V. Nyuchev、Nico Erdmann、Volker Hessel、Franziska Schoenebeck、Timothy Noël
DOI:10.1039/c6sc02595a
日期:——
A mild and selective C–Harylation strategy for indoles, benzofurans and benzothiophenes is described. The arylation method engages aryldiazonium salts as arylating reagents in equimolar amounts. The protocol is operationally simple, base free, moisture tolerant and air tolerant. It utilizes low palladium loadings (0.5 to 2.0 mol% Pd), short reaction times, green solvents (EtOAc/2-MeTHF or MeOH) and
Selective carbon–carbon bond activation is important in chemical industry and fundamental organic synthesis, but remains challenging. In this study, non-polar unstrained Csp2–Csp3 and Csp2–Csp2 bond activation was achieved by B(OMe)3/B2pin2-mediated fragmentation borylation. Various indole derivatives underwent C2-regioselective C–C bond activation to afford two C–B bonds under transition-metal-free
Pd(0)-Catalyzed Decarboxylative Coupling and Tandem C–H Arylation/Decarboxylation for the Synthesis of Heteroaromatic Biaryls
作者:Debkumar Nandi、Yang-Ming Jhou、Jhen-Yi Lee、Bing-Chiuan Kuo、Chien-Yu Liu、Pei-Wen Huang、Hon Man Lee
DOI:10.1021/jo3015837
日期:2012.10.19
An effective Pd(0) carbene complex was successfully employed in the decarboxylative coupling of the heteroaromatic carboxylic acids (imidazo[1,2-a]pyridine and isoxazole) with aryl halides. For carboxyindoles, either decarboxylative coupling or tandem C-H arylation and decarboxylation occurred, leading to the formation of C2-monoarylated indoles.