A decarboxylative approach for regioselective hydroarylation of alkynes
作者:Jing Zhang、Ruja Shrestha、John F. Hartwig、Pinjing Zhao
DOI:10.1038/nchem.2602
日期:2016.12
group that activates one of several aromatic C–H bonds. Here we report a new catalytic method for regioselective alkyne hydroarylation with benzoicacid derivatives during which the carboxylate functionality directs the alkyne to the ortho-C–H bond with elimination in situ to form a vinylarene product. The decarboxylation stage of this tandem sequence is envisioned to proceed with the assistance of
The Diels-Alder reaction of methyl 2-pyrone-5-carboxylate and bis(trimethylsilyl)acetylene gave methyl 3,4-bis(trimethylsilyl)-benzoate which was transformed into [5-(methoxycarbonyl)-2-(trimethylsilyl)phenyl](phenyl)iodonium triflate by the reaction with a hypervalent iodine reagent PhI(OAc)2/TfOH. The generation and trapping reactions of 4-(methoxycarbonyl)-1,2-didehydrobenzene were successfully conducted by the reaction of the iodonium triflate with Bu4NF.
Palladium nanoparticles and sodium acetate catalyze the reaction of aryl bromide with diarylacetylene to produce annulated products in good yield. One equivalent of PEG-600 serves as the solvent. This procedure is compatible with a wide variety of functional groups.
On the use of 2-(trimethylsilyl)iodobenzene as a benzyne precursor
作者:James A. Crossley、James D. Kirkham、Duncan L. Browne、Joseph P.A. Harrity
DOI:10.1016/j.tetlet.2010.10.052
日期:2010.12
A mild method for the generation of benzynes from 2-(trimethylsilyl)iodobenzene derivatives is reported. The employment of silver fluoride in conjunction with caesium fluoride is key for promoting useful levels of elimination and providing benzyne derived products in good yields. Moreover, the substrates are accessed by a novel alkynyl iodide cycloaddition.
The rhodium-catalyzed oxidative 1:2 coupling reactions of arylboronic acids or their esters with alkynes smoothly proceed to produce the corresponding annulated products. Of special note, highly substituted, readily soluble, and tractable anthracene and tetracene derivatives can be obtained selectively from 2-naphthyl- and 2-anthrylboron reagents, respectively.