Palladium-Catalyzed Cross-Coupling of β-(Methanesulfonyl)oxy Enones with Organostannanes

Article abstract of DOI:10.1021/jo00004a028

β-(Methanesulfonyl)oxy enones, derived from 1,3-diones, cross-couple with vinylstannanes in 50-80percent yields when a substoichiometric amount of Pd(PPh3)4 and stoichiometric lithium bromide are used.Phenyltributylstannane affords low yields of cross-coupled product.Tetrabutyltin, tributyltin hydride, and ethynyltributyltin do not couple under the reaction conditions.The reaction is proposed to involve in situ formation of the β-bromo enone, oxidative addition to the Pd(0) catalyst, transmetalation, and reductive elimination to afford cross-coupled products.The analogous enol phosphates undergo coupling in low yields, the major product resulting from regeneration of the 1,3-dione.