B2pin2-Mediated Palladium-Catalyzed Diacetoxylation of Aryl Alkenes with O2 as Oxygen Source and Sole Oxidant
摘要:
A novel palladium-catalyzed alkene diacetoxylation with dioxygen (O-2) as both the sole oxidant and oxygen source is developed, which was identified by O-18-isotope labeling studies. Control experiments suggested that bis(pinacolato)diboron (B(2)pin(2)) played a dominant intermediary role in the formation of a C-O bond. This method performed good functional group tolerance with moderate to excellent yields, which could be successfully applied to the late-stage modification of natural products. Furthermore, an atmospheric pressure of dioxygen enhances the practicability of the protocol.
Pincer Complex-Catalyzed Redox Coupling of Alkenes with Iodonium Salts via Presumed Palladium(IV) Intermediates
作者:Juhanes Aydin、Johanna M. Larsson、Nicklas Selander、Kálmán J. Szabó
DOI:10.1021/ol9010739
日期:2009.7.2
Palladium pincer complexes directly catalyze the redox coupling reactions of functionalized alkenes and iodonium salts. The catalytic process, which is suitable for mild catalytic functionalization of allylic acetates and electron-rich alkenes, probably occurs through Pd(IV) intermediates. Due to the strong metal−ligand interactions, the oxidation of phosphine and amine ligands of the pincer complexes
Highly Regio- and Stereoselective Heck Reaction of Allylic Esters with Arenediazonium Salts: Application to the Synthesis of Kavalactones
作者:Angélica Venturini Moro、Flávio Sega Pereira Cardoso、Carlos Roque Duarte Correia
DOI:10.1021/ol901416e
日期:2009.8.20
highly efficient palladium-catalyzed Heck reaction of allylic esters with arenediazoniumsalts is described. The reaction proceeds under mild conditions, with excellent to total regio- and stereochemical control and with retention of the traditional leaving group. Furthermore, the generality of the present methodology is illustrated by the short total synthesis of the natural kavalactones, yangonine,