Stereoselective Synthesis of Tetrasubstituted Alkenes from 1,2-Diketones via Oxyphosphonium Salts-Engaged Suzuki-Miyaura Coupling

We report an efficient and stereoselective synthesis of tetrasubstituted alkenes through palladium-catalyzed Suzuki-Miyaura coupling of arylboronate esters with O-alkenyl oxyphosphonium salts. These electrophilic partners are prepared from 1,2-diketones via the Kukhtin-Ramirez reaction followed by O-methylation. The protocol achieves high yields and excellent Z/E selectivity using Pd(OAc)₂ with commercially available phosphine ligands, wherein ligand selection enables stereochemical control. Preliminary mechanistic studies suggest that the isomerization of the critical alkenyl-palladium intermediate dictates the product configuration. By integrating Kukhtin-Ramirez chemistry with cross-coupling technology, this methodology establishes a streamlined platform for converting 1,2-diketones into synthetically challenging tetrasubstituted alkenes.