Asymmetric aldol addition of alpha-azido ketones to ethyl pyruvate mediated by a cinchona-based bifunctional urea catalyst

Okumus, Seda
Tanyeli, Cihangir
Demir, Ayhan Sıtkı
The first asymmetric synthesis of ethyl 4-aryl-3-azido-2-hydroxy-2-methyl-4-oxobutanoates via a cinchona organocatalyst induced aldol addition of alpha-azido ketones to ethyl pyruvate has been developed. The coupling reaction under optimized conditions was carried out to furnish tetrafunctionalized synthons with enantioselectivities of up to 91:9 and enriched diastereoselectivities of up to 95:5 (syn:anti).


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We described the unusual results of manganese(III) acetate based tandem oxidation of various alpha and beta-alkoxy alpha,beta-unsaturated ketones to afford the corresponding alpha'-acetoxy-alpha'-phenyl substituted oxidation products in good yields. The tandem oxidation to monoacetoxylation ratio can be tuned by the amount of manganese(III) acetate.
Citation Formats
S. Okumus, C. Tanyeli, and A. S. Demir, “Asymmetric aldol addition of alpha-azido ketones to ethyl pyruvate mediated by a cinchona-based bifunctional urea catalyst,” TETRAHEDRON LETTERS, pp. 4302–4305, 2014, Accessed: 00, 2020. [Online]. Available: