Axially chiral N,N'-dioxides ethers for catalysis in enantioselective allylation of aldehydes.

A series of axially chiral ethers synthesized from biscarboline N,N'-dioxides, (S)-1a to (S)-1n, was investigated in enantioselectivity addition reactions of allyltrichlorosilane with a series of substituted aldehydes, including bulky substituted aldehydes. High enantioselectivities (up to 96%ee) were achieved using the catalyst (S)-1k at 1 mol % loading.