Stereoretentive Pd-Catalyzed Kumada−Corriu Couplings of Alkenyl Halides at Room Temperature

actions of functionalized alkenyl halides and a variety of Grignard reagents, including those bearing β-hydrogen atoms and sensitive functional groups, can be carried out at room temperature using a new combination of reagents. Kumada−Corriu cross-couplings are among the earliesttransition-metal-catalyzed reactions introduced as a means of forming carbon−carbon bonds.1 Initially reported as nickel-catalyzed processes between Grignard reagents and aryl or alkenyl halides, subsequent developments in palladium-catalyzed couplings have led to variations based on this less toxic and more functional group tolerant process, as first reported by Murahashi.2 While these Pd-catalyzed couplings are highly effective for biaryl formation, those involving alkenyl halides together with alkyl Grignard reagents bearing β-hydrogens are notoriously problem-atic, owing to the considerable potential for competing β-hydride elimination.3 Although great progress has been made towar