Journal of Organic Chemistry 2011-04-15

Chelation-mediated palladium(II)-catalyzed domino Heck-Mizoroki/Suzuki-Miyaura reactions using arylboronic acids: increasing scope and mechanistic understanding.

Samir Yahiaoui, Ashkan Fardost, Alejandro Trejos, Mats Larhed

Index: J. Org. Chem. 8th ed., 76 , 2433-2438, (2011)

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Abstract

A palladium(II)-catalyzed Heck-Mizoroki/Suzuki-Miyaura domino reaction involving metal coordinating dimethylaminoethyl vinyl ethers and a number of electron-rich and electron-deficient arylboronic acids has been developed. Through variation of the temperature and the concentration of the p-benzoquinone (p-Bq) ligand/reoxidant, conditions for the robust and convenient one-pot generation of diarylated-saturated ethers were identified. With the aid of coordination of the dimethylamino group to the arylpalladium intermediate, the otherwise predominant formation of the β-arylated olefin could be reversed. A reaction route involving a chelation-controlled carbopalladation, providing a p-Bq stabilized six-membered palladacycle, followed by transmetalation and reductive elimination is suggested to explain the selective formation of saturated diarylated ether products.