Continuous Flow, Highly Enantioselective Michael Additions Catalyzed by a PS-Supported Squaramide
journal contributionposted on 19.07.2013, 00:00 by Pinar Kasaplar, Carles Rodríguez-Escrich, Miquel A. Pericàs
A polystyrene (PS) supported bifunctional squaramide organocatalyst promotes fast Michael addition of 2-hydroxy-1,4-naphthoquinone to nitroalkenes with very high enantioselectivities at low catalyst loadings. The polystyrene supported catalyst can be recycled up to 10 times without any decrease in enantioselectivity (average 96% ee) and adapted to continuous flow operation (24 h). A single flow experiment involving six different nitroalkenes in a sequential manner highlights the applicability of this methodology for rapid access to chemical diversity.