Convenient Practical Alkynylation of Heteronucleophiles with Copper Acetylides

Copper acetylides, readily available reagents which are characterized by their lack of reactivity, can be simply activated by oxidation with oxygen in the presence of simple nitrogen ligands such as TMEDA or imidazole derivatives. Upon activation, these nucleophilic species undergo a formal umpolung and can transfer their alkyne subunit to a wide range of heteronucleophiles, including amides, oxazolidinones, imines, and dialkyl phosphites. This alkynylation, which provides one of the most practical entry to useful building blocks such as ynamides, ynimines, and alkynylphosphonates, proceeds under especially mild conditions and can be easily performed on a multigram scale.