Publication Details (including relevant citation information): Opalka, Suzanne M., Steinbacher, Jeremy L., Lambiris, Brandon A., McQuade, D. Tyler, J. Org. Chem., 2011, 76 (16), pp 6503-6517
Abstract: A thiourea/proline derivative-catalyzed synthesis of linear α-substituted tetrahydrofuran/pyran derivatives starting with lactol substrates is presented. This study demonstrates the utility and potential complications of using (thio)urea/proline cocatalysis as each of these catalysts is necessary to provide the observed reactivity, but a time-dependent decrease in enantioselectivity is observed. New mechanistic insights into (thio)urea/proline cocatalysis are presented.
Address (URL): http://dx.doi.org/10.1021/jo200838v