A Dual Palladium and Copper Hydride Catalyzed Approach for Alkyl-Aryl Cross-Coupling of Aryl Halides and Olefins

We report an efficient means of sp(2)-sp(3) cross coupling for a variety of terminal monosubstituted olefins with aryl electrophiles using Pd and CuH catalysis. In addition to its applicability to a range of aryl bromide substrates, this process was also suitable for electron-deficient aryl chlorides, furnishing higher yields than the corresponding aryl bromides in these cases. The optimized protocol does not require the use of a glovebox and employs air-stable Cu and Pd complexes as precatalysts. A reaction on 10 mmol scale further highlighted the practical utility of this protocol. Employing a similar protocol, a series of cyclic alkenes were also examined. Cyclopentene was shown to undergo efficient coupling under these conditions. Lastly, deuterium-labeling studies indicate that deuterium scrambling does not take place in this sp(2)-sp(3) cross coupling, implying that beta-hydride elimination is not a significant process in this transformation.