Electrostatic Repulsion and Hydrogen‐Bonding Interactions in a Simple N‐Aryl‐L‐valinamide Organocatalyst Control the Stereoselectivity in Asymmetric Aldol Reactions. Issue 29 (2nd September 2013)

• Record Type: Journal Article
• Authors: Tanimura, Yuya; Yasunaga, Kenji; Ishimaru, Kaori
• Is Part Of: European journal of organic chemistry. Issue 29(2013)
• Page Start: 6535
• Page End: 6539
• Publication Date: 2013-09-02
• Subjects: Synthetic methods -- Organo­catalysis -- Asymmetric catalysis -- Aldol reactions­ -- Heterocycles; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201301138
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: A novel stereocontrol method for asymmetric aldol reactions of aldehydes with ketones is described. The stereoselectivity of the products is controlled by the electrostatic repulsion and hydrogen‐bonding interactions of an N ‐aryl‐L ‐valinamide catalyst. The use of this catalyst in a cross‐aldol reaction allows easy access to bioactive 3‐cyclohexanone‐3‐hydroxy‐2‐oxindole with excellent diastereo‐ ( syn / anti = >99:1) and enantioselectivity (>99 % ee ). Abstract : Small, simple, and flexible N ‐(2, 6‐difluorophenyl)‐L ‐valinamide controls the stereoselectivity in asymmetric aldol and cross‐aldol reactions under environmentally friendly conditions. The use of this catalyst in a cross‐aldol reaction allows easy access to bioactive 3‐hydroxy‐3‐(2‐oxocyclohexyl)indolin‐2‐one with excellent diastereo‐ and enantioselectivities.