Synthesis of Phosphine-Ligated Zinc Acetylide Dimers: Enhanced Reactivity in Carbonyl Additions

Phosphine-ligated dinuclear zinc acetylides effectively promote the alkynylation of carbonyl derivatives. Good to excellent yields (46–91%) of the corresponding propargylic alcohols were obtained from a wide range of substrates. Crystallographic evidence for a phosphine–zinc–acetylide dimer was obtained with bonding energies obtained by DFT calculations. Phosphine ligation in the carbon–carbon bond-forming event is further corroborated by the synthesis of an enantioenriched propargylic alcohol through the addition of chiral phosphines.