1331830-93-3Relevant articles and documents
Dual catalysis in enantioselective oxidopyrylium-based [5 + 2] cycloadditions
Burns, Noah Z.,Witten, Michael R.,Jacobsen, Eric N.
, p. 14578 - 14581 (2011/10/17)
A new method for effecting catalytic enantioselective intramolecular [5 + 2] cycloadditions based on oxidopyrylium intermediates is reported. The dual catalyst system consists of a chiral primary aminothiourea and a second achiral thiourea. Experimental evidence points to a new type of cooperative catalysis with each species being necessary to generate a reactive pyrylium ion pair that undergoes subsequent cycloaddition with high enantioselectivity.