Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5279386 | Tetrahedron Letters | 2006 | 4 Pages |
The catalytic system composed of CuCl2 and 2,2â²-biquinoline-4,4â²-dicarboxylic acid dipotassium salt (BQC) was found to be highly efficient for the selective α-oxidation of internal alkynes to the corresponding α,β-acetylenic ketones, with aqueous tert-butyl hydroperoxide under mild conditions. For the first time, full conversions of alkynes were reached with excellent selectivities, and propargylic tert-butylperoxy ethers were observed and suggested as the reaction intermediates. In the case of terminal alkynes, the oxidations are sluggish and low yields ranging from 32% to 40% were obtained.
Graphical abstractThe water-soluble complex generated in situ from CuCl2 and 2,2â²-biquinoline-4,4â²-dicarboxylic acid dipotassium salt (BQC) has been revealed as a highly efficient catalyst for the selective α-oxidation of internal alkynes to the corresponding α,β-acetylenic ketones, with aqueous tert-butyl hydroperoxide, under mild conditions. For the first time, full conversions of alkynes were reached with excellent selectivities, and propargylic tert-butylperoxy ethers were observed and suggested as the reaction intermediates. In the case of terminal alkynes, the oxidations are sluggish and low yields ranging from 32% to 40% were obtained.Download full-size image