(2S)-4-Iodo-3-butyne-1,2-diol (320mg, 1 equiv.)
1-tert-Butyldimethylsilyloxyprop-2-yne (462mg, 1.8 equiv.)
Copper(I) iodide (washed with dry THF and dried in vacuum, 29mg, 0.1 equiv.)
Pyrrolidine (freshly distilled, 1.5 mL, 1 mL/mmol

The two alkynes are stirred together at 0 ^oC in pyrrolidine and the copper iodide is added in one portion, initially creating a green coloured solution which quickly turns red/brown. The reaction is stirred at this temperature for 30 minutes-1 hour until completion (TLC), then quenched with ammonium chloride solution, extracted 4 times with ether, washed with brine, dreid over magnesium sulphate, filtered and concentrated. Purification is achieved by column chromatography eluting with 20-50% EtOAc/PE.

In order to attain reliable yields, purification of reagents as detailed is necessary and the reaction must be kept at 0^oC (although not all substrates require reduced temperatures; see lead reference). It should be monitored regularly by TLC as it can proceed very rapidly, and decomposition will occur if the reaction is continued stirring after it is complete. If these conditions are observed, yields of greater than 80% are possible. Further examples carried out include the coupling of triethylsilylacetylene, although due to the reduced stability if the TES group, the yields tend to be somewhat less (60-70%). It is also interesting to note that the reaction fails completely with trimethylsilylacetylene, presumably due to the lability of the TMS group.

¹H NMR (300MHz, CDCl₃) d 4.40 (1H, t, J=4.6), 4.26 (2H, s), 3.56-3.66 (2H, m), 2.26 (1H, br s, exch.), 1.95 (1H, br s, exch.), 0.78 (9H, s), 0.00 (6H, s).

Alami M., Ferri F. Tetrahedron Lett. 1996 p.2763

Hirama M., Iguchi S., Wang G.X. J. Org. Chem. 2001 p.2146