(American Chemical Society, 2011) Jacobsen, Eric; Beck, Elizabeth M.; Hyde, Alan M.
The application of chiral sulfinamides and achiral sulfonic acids as a co-catalyst system for enantioselective protonation reactions is described. Structurally simple, easily accessible sulfinamides were found to induce moderate-to-high eeʼs in the formation of 2-aryl-substituted cycloalkanones from the corresponding trimethylsilyl enol ethers.
(American Chemical Society, 2011) Burns, Noah; Witten, Michael R.; Jacobsen, Eric
A new method is reported for effecting catalytic enantioselective intramolecular [5+2] cycloadditions based on oxidopyrylium intermediates. 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 which undergoes subsequent cycloaddition with high enantioselectivity.
