Selective oxidation of alkenes and alkynes catalyzed by copper complexes

Benzoic esters of 2-cyclohexen-1-ol and propargylic alcohols were prepared by direct selective copper-catalyzed allylic and propargylic oxidation of alkenes and alkynes, respectively, using t-butyl peroxybenzoate as the oxidant. The high olefin and acetylene conversions as well as the high product yields were obtained although enantioselectivity of this oxidation was moderate (e.e. < 68%). The reported optimized catalytic procedure is clean since the oxidation is carried out under mild conditions using stoichiometric amounts of oxidant and catalytic amounts of (CuOTf)2C6H6 in combination with bisoxazoline ligands.