Synthesis of diynes and tetraynes from in situ desilylation/dimerization of acetylenes

[GRAPHICS] An efficient method for the in situ desillylation/oxidative dimerization of (trialkylsilyl)acetylenes is described. This protocol avoids the complicat ions encountered with sensitive diynes by eliminating the deprotection and isolation steps. Various aromatic and alkyl diynes and tetraynes can be syn thesized in a straightforward manner in good yields (82-99%) from TIPS-prot ected acetylenes. This method facilitates the efficient synthesis of novel tetrayne-bridged acetylenic cyclophanes 6 and 7 in a direct manner.