A Convenient Negishi Protocol for the Synthesis of Glycosylated Oligo(ethynylene)s

A convenient and efficient sp-sp carbon heterocoupling protocol based on the Negishi reaction was developed, in which the required zinc diacetylide was generated from 1,4-bis(trimethylsilyl)butadiyne in situ and reacted with a bromoacetylene in apolar solvent mixtures. The method has been applied to the synthesis of unsymmetric glycosylated and symmetric diglycosylated oligo(ethynylene)s up to the octa(ethynylene).