Enantioselective aldol reactions of trichlorosilyl enol ethers catalyzed by chiral N,N′-dioxides and monodentate N-oxides

Chiral N,N′-dioxides and monodentate N-oxides were employed as catalysts in catalytic, enantioselective aldol reactions of trichlorosilyl enol ethers. The reactions of acyclic enol ethers using N,N′-dioxides resulted in the anti-adducts from (E)-enol ethers and the syn-adducts from (Z)-enol ethers. The reactions of cyclic (E)-enol ethers using N,N′-dioxides gave the anti-adducts, whereas monodentate N-oxides predominantly gave the syn-adducts.