General Methodology for the Preparation of Unsymmetrical α-Linked Bisenones via Ligandless Cross-Coupling Reactions.

A stereocontrolled Stille cross-coupling reaction, involving the use of Pd2 dba3 , provides a general procedure for the synthesis of unsymmetrical α-linked bisenone systems. The transformation is achieved in the absence of phosphine ligands under conditions that promote the stabilization of "ligandless" palladium catalysis. The extension of these studies illustrates Suzuki-Miyaura reactions of 2-boryl-2-cyclohexen-1-one with iodide and triflate partners for the synthesis of novel electron-deficient 1,3-dienes.