Planar-Chiral Thioureas as Hydrogen-Bond Catalysts

• Published in: European Journal of Organic Chemistry Vol. 2010; no. 12; pp. 2265 - 2269
• Main Authors: Schneider, Jakob F., Falk, Florian C., Fröhlich, Roland, Paradies, Jan
• Format: Book Review Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01-04-2010; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Alicyclic compounds; Alicyclic compounds, terpenoids, prostaglandins, steroids; Chemistry; Chirality; Cyclophanes; Exact sciences and technology; Heterocyclic compounds; Heterocyclic compounds with only one n hetero atom and condensed derivatives; Hydrogen bonds; Organic chemistry; Organocatalysis; Preparations and properties; Thioureas; Nitro compound; Bifunctional catalyst; Cyclophanes; Nitrogen heterocycle; Chiral compound; Thioureas; Hydrogenation; Organocatalysis; Macrocycle; Planar molecule; Organic synthesis; Friedel Crafts reaction; Asymmetric synthesis; Hydrogen bonds; Chirality; Catalysis; Cyclophane; Indole derivatives; Chemical synthesis; Hydrogen bond
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.200901353

The synthesis of the first enantiopure planar‐chiral thiourea catalysts is herewith described. New catalysts 1–3 were applied in asymmetric transformations, such as the Friedel–Crafts alkylation of indole, as well as in the transfer hydrogenation of nitroolefins. Bifunctional catalysts 2 and 3 exhibit enhanced activity in the investigated reactions, demonstrating their potential for organic synthesis.
The first planar‐chiral thiourea hydrogen‐bond catalysts were synthesized from the corresponding [2.2]paracyclophanylamines. Enantiopure bifunctional thioureas operate as hydrogen‐bond catalysts and display enhanced activity in comparison to their monofunctionalized derivatives.