Synthesis of Conjugated Allenes through Copper-Catalyzed γ-Selective and Stereospecific Coupling between Propargylic Phosphates and Aryl- or Alkenylboronates

A Cu-catalyzed gamma-selective coupling reaction between propargylic phosphates and aryl- or alkenylboronates afforded aryl- or alkenyl-conjugated allenes. The reaction showed excellent functional group compatibility in both the propargylic substrates and the boronates. The reaction of an enantioenriched propargylic phosphate proceeded with excellent chirality transfer with 1,3-anti stereochemistry to give axially chiral aryl- and alkenylallenes.