Enantioselective thiourea-catalyzed additions to oxocarbenium ions

…, AG Doyle, EN Jacobsen

Index: Reisman, Sarah E.; Doyle, Abigail G.; Jacobsen, Eric N. Journal of the American Chemical Society, 2008 , vol. 130, # 23 p. 7198 - 7199

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Citation Number: 256

Abstract

Asymmetric, catalytic reactions of oxocarbenium ions are reported. Simple, chiral urea and thiourea derivatives are shown to catalyze the enantioselective substitution of silyl ketene acetals onto 1-chloroisochromans. A mechanism involving anion binding by the chiral catalyst to generate a reactive oxocarbenium ion is invoked. Catalysts bearing tertiary benzylic amide groups afforded highest enantioselectivities, with the optimal structure ...