Addition of aldehydes with allyltrichlorosilane catalyzed by chiral bis-N-O secondary amides

New axially N-oxide amides derived from l-tryptophan were prepared and used as organocatalysts in enantioselective allylation of aromatic aldehydes with allyltrichlorosilanes. The corresponding addition adducts homoallylic chiral alcohols obtained high enantioselectivities (up to 96% ee) when 1 mol % of catalyst was used. The unexpected result is the addition product's absolute configuration is R when (R)-chiral amides was used, in contrast, it was (S) when (R)-chiral methyl ester were used in allylation. It exhibited that the N atoms of amides take part in the transition state procedure.

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