the synthesis of alkynylphosphine oxides based on the oxidative alkynylation of secondary phosphineoxides with copper acetylides was developed. Activation with molecular oxygen in the presence of either a mixture of 1,2-dimethylimidazole and triethylamine or N-methylimidazole alone enabled the formal umpolung of the poorly nucleophilic copper acetylides, which were coupled with phosphineoxides under
An original and user-friendly synthesis of alkynylphosphine-boranes, useful building blocks in organic synthesis, based on an oxidative P-alkynylation reaction with readily available copper acetylides is reported. The ability of a secondary phosphine protected with a borane to undergo oxidative coupling without oxidation of the P-moiety is demonstrated for the first time. The reaction, which proceeds at room temperature, is applicable to the preparation of enantioenriched and structurally complex alkynylphosphine-boranes.