Publication – Continuous flow enantioselective α-aminoxylation of aldehydes catalyzed by a polystyrene-immobilized hydroxyproline

Beilstein Journal of Organic Chemistry, 2011, 7, 1486-1493

• Xacobe C Cambeiro, Rafael Martín-Rapún, Pedro O Miranda, Sonia Sayalero, Esther Alza, Patricia Llanes, and Miquel A Pericàs
• Institute of Chemical Research of Catalonia (ICIQ) Avda. Paisos Catalans, 16. E-43007, Tarragona, Spain

This paper describes a versatile enantioselective α-aminoxylation process in flow using a solid supported catalyst. The use of flow chemistry allows improved conversion rates thanks to the high contact surface between reagent and catalyst and also simplifies the scale-up of this reaction.

This synthesis was performed using an Asia system. Please see below a video in which the authors discuss the reaction and show the practical setup.

Abstract: The application of polystyrene-immobilized proline-based catalysts in packed-bed reactors for the continuous-flow, direct, enantioselective α-aminoxylation of aldehydes is described. The system allows the easy preparation of a series of β-aminoxy alcohols (after a reductive workup) with excellent optical purity and with an effective catalyst loading of ca. 2.5% (four-fold reduction compared to the batch process) working at residence times of ca. 5 min.

This paper uses an Asia flow chemistry system.