A New Approach to Axially Chiral Bipyridine <i>N,N′‐</i>Dioxides Bearing Aromatic Substituents and their Use for Catalytic Asymmetric Allylation of Aldehydes with Allyl(trichloro)silane

Abstract

Abstract Palladium‐catalyzed cross‐coupling of bipyridine N,N′ ‐dioxide 6,6′‐dichloride ( R nap ,R pyr )‐ 1 with the aryl Grignard reagents opened a new approach to axially chiral bipyridine N,N′‐ dioxides ( R )‐ 2 bearing a variety of aryl groups at the 6 and 6′ positions. One of the N,N′‐ dioxides ( R )‐ 2d which is substituted with 3,5‐dimethyl‐4‐methoxy groups was found to be highly catalytically active and enantioselective for the asymmetric allylation of aldehydes with allyl(trichloro)silane. The allylation took place with 0.01–0.1 mol % of ( R )‐ 2d giving homoallyl alcohols of up to 94% ee.