[reaction: see text] One-pot allene synthesis from aryl iodides 1 and propargyldicyclohexylamine 2 proceeded in the presence of Pd(2)(dba)(3).CHCl(3) catalyst (2.5 mol %), 1,2-bis(diphenylphosphino)carborane 5 (10 mol %), CuI (15 mol %), and Et(3)N (150 mol %) to give the corresponding allenes 4 in good to high yields. Electron-deficient bidentate phosphines, such as 1,2-bis(diphenylphosphino)carborane 5 and (C(6)F(5))(2)PC(2)H(4)P(C(6)F(5))(2), play the role of a dual mode ligand for both the Sonogashira coupling and hydride-transfer reactions.
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