Urea- and Thiourea-Substituted Cinchona Alkaloid Derivatives as Highly Efficient Bifunctional Organocatalysts for the Asymmetric Addition of Malonate to Nitroalkenes: Inversion of Configuration at C9 Dramatically Improves Catalyst Performance

• Published in: Angewandte Chemie (International ed.) Vol. 44; no. 39; pp. 6367 - 6370
• Main Authors: McCooey, Séamus H., Connon, Stephen J.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 07.10.2005; WILEY‐VCH Verlag; Wiley
• Subjects: Alkenes - chemical synthesis; Alkenes - chemistry; asymmetric catalysis; Catalysis; Chemistry; Chemistry, Multidisciplinary; cinchona alkaloids; Cinchona Alkaloids - chemical synthesis; Cinchona Alkaloids - chemistry; Malonates - chemistry; Michael addition; Models, Chemical; Molecular Structure; Nitro Compounds - chemical synthesis; Nitro Compounds - chemistry; organocatalysis; Physical Sciences; Science & Technology; Stereoisomerism; Thiourea - chemistry; Urea - chemistry; ureas; Michael addition; DIELS-ALDER REACTIONS; LEWIS-ACID; 1,3-DICARBONYL COMPOUNDS; BAYLIS-HILLMAN REACTION; asymmetric catalysis; DYNAMIC KINETIC RESOLUTION; cinchona alkaloids; organocatalysis; AMINO-ACIDS; ENANTIOSELECTIVE CONJUGATE ADDITION; ureas; MICHAEL ADDITIONS; STRECKER REACTION; METAL-FREE
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.200501721

Natural not always best: Novel N‐aryl urea and thiourea derivatives of dihydrocinchona alkaloids serve as efficient catalysts for the asymmetric addition of dimethyl malonate to a range of nitroalkenes. Catalytic activity and selectivity depend strongly on the relative configuration at C8/C9. Catalysts with “non‐natural” inverted configuration at C9 display excellent activity and enantioselectivity at loadings as low as 0.5 mol %.