Copper-catalysed photoinduced decarboxylative alkynylation: a combined experimental and computational study |
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| Authors: | Yu Mao Wenxuan Zhao Shuo Lu Lei Yu Yi Wang Yong Liang Shengyang Ni Yi Pan |
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| Institution: | State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023 China, |
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| Abstract: | Redox-active esters (RAEs) as alkyl radical precursors have demonstrated great advantages for C–C bond formation. A decarboxylative cross-coupling method is described to afford substituted alkynes from various carboxylic acids using copper catalysts CuCl and Cu(acac)2. The photoexcitation of copper acetylides with electron-rich NEt3 as a ligand provides a general strategy to generate a range of alkyl radicals from RAEs of carboxylic acids, which can be readily coupled with a variety of aromatic alkynes. The scope of this cross-coupling reaction can be further expanded to aliphatic alkynes and alkynyl silanes using a catalytic amount of preformed copper-phenylacetylide. In addition, DFT calculations revealed the favorable reaction pathway and that the bidentate acetylacetonate ligand of the copper intermediate plays an important role in inhibiting the homo-coupling of the alkyne.Redox-active esters (RAEs) as alkyl radical precursors have demonstrated great advantages for Cu-catalysed C–C bond formation. |
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