Synthesis of conjugated bisallenes by cooperative Cu/Pd-catalysed borylallenylation of 2-trifluoromethyl-1,3-enynes.

A cooperative Cu/Pd-catalysed borylallenylation of 2-trifluoromethyl-1,3-enynes with propargylic carbonates under mild reaction conditions was developed. This method provides facile and efficient access to conjugated bisallenes with a broad range of functional groups. Both aromatic and aliphatic 1,3-enynes can be utilized in this transformation to give the corresponding multi-substituted conjugated bisallenes.