Asymmetric Catalysis on the Nanoscale: The Organocatalytic Approach to Helicenes. Issue 20 (15th April 2014)

• Record Type: Journal Article
• Authors: Kötzner, Lisa; Webber, Matthew J.; Martínez, Alberto; De Fusco, Claudia; List, Benjamin
• Is Part Of: Angewandte Chemie international edition. Volume 53:Issue 20(2014)
• Page Start: 5202
• Page End: 5205
• Publication Date: 2014-04-15
• Subjects: Brønsted acid catalysis -- Fischer indole synthesis -- helicenes -- organocatalysis; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201400474
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The first asymmetric organocatalytic synthesis of helicenes is reported. A novel SPINOL‐derived phosphoric acid, bearing extended π‐substituents, catalyzes the asymmetric synthesis of helicenes through an enantioselective Fischer indole reaction. A variety of azahelicenes and diazahelicenes could be obtained with good to excellent yields and enantioselectivities. Abstract : Twisting indoles : A novel chiral Brønsted acid, specifically designed for long‐range control on a nanoscale, catalyzes the asymmetric synthesis of azahelicenes through a Fischer indolization. The method has the advantage of starting from simple achiral starting materials, which can be modified by changing the protecting group (R 2 ) or the terminal substituents (R 1, R 3 ). The products can be further oxidized to polyaromatic systems.