Propargylic C[sbnd]H activation using a Cu(II) 2-quinoxalinol salen catalyst and tert-butyl hydroperoxide

Abstract

The oxidation of alkynes to α,β-acetylenic carbonyls was achieved using only 1 mol% of a Cu(II) 2-quinoxalinol salen catalyst with tert-butyl hydroperoxide. These reactions proceed under mild conditions (70 °C) with excellent selectivity, producing yields up to 78%, and were used on a variety of alkyne substrates to produce the desired corresponding α,β-acetylenic ketones. In addition, these reactions can be run under aqueous conditions using a sulfonated version of the 2-quinoxalinol salen with good yields, reducing the need for volatile organic solvents.