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

作者：Okumus Seda; Tanyeli Cihangir^*; Demir Ayhan S

来源：Tetrahedron Letters, 2014, 55(31): 4302-4305.

DOI：10.1016/j.tetlet.2014.06.018

• Aldol reaction
• alpha-Azido ketone
• Bifunctional urea
• C-C coupling
• Cinchona alkaloids

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).

• 出版日期2014-7-30