Chiral bipyridine-annulated bicyclo[3.3.1]nonane N-oxide organocatalysts for stereoselective allylation and hydrosilylation reactions

Abstract

Abstract The synthesis of chiral C2-symmetric bis(bipyridine N,N′-dioxide) and bis(bipyridine N-monooxide) derivatives featuring bipyridine-annulated bicyclo[3.3.1]nonane framework is reported. The new Lewis basic bipyridine N,N′-dioxides exhibited good catalytic activity in the asymmetric allylation of aldehydes with allyltrichlorosilane, furnishing corresponding homoallylic alcohols in up to 75% ee. Reduction of ketimines and β-enamino esters with trichlorosilane catalyzed by bipyridine N,N′-dioxides proceeded in high yields but modest enantioselectivity (38–54% ee); good levels of asymmetric induction (up to 73% ee) were attained in the reduction of α-imino esters at room temperature.