Asymmetric <i>Aza-</i>[3 + 3] Annulation in the Synthesis of Indolizidines: An Unexpected Reversal of Regiochemistry
作者:Grant S. Buchanan、Huifang Dai、Richard P. Hsung、Aleksey I. Gerasyuto、Casi M. Scheinebeck
DOI:10.1021/ol2017438
日期:2011.8.19
An enantioselective and diastereoselective aza-[3 + 3] annulation of pyrrolidine-based exo-cyclic vinylogous amides and urethanes with chiral vinyl iminium salts is described. This asymmetric annulation manifold is possible because of an unexpected regiochemical reversal whereby head-to-tall annulations dominated over the predicted head-to-head. It should find prevalent synthetic applications in the enantioselective synthesis of indolizidines.