Enantioselective Oxidative (4+3) Cycloadditions between Allenamides and Furans through Bifunctional Hydrogen-Bonding/Ion-Pairing Interactions
作者:Laura Villar、Uxue Uria、Jose I. Martínez、Liher Prieto、Efraim Reyes、Luisa Carrillo、Jose L. Vicario
DOI:10.1002/anie.201704804
日期:2017.8.21
N‐trifluoromethanesulfonyl phosphoramides catalyze the enantioselective (4+3) cycloaddition between furans and oxyallyl cations, the latter being generated in situ by oxidation of allenamides. The chiral organic phosphoramide counteranion is proposed to engage in the activation of the oxyallyl cation intermediate through cooperative hydrogen‐bonding and ion‐pairing interactions, enabling an efficient chirality
基于BINOL的N-三氟甲磺酰基磷酰胺可催化呋喃和氧烯丙基阳离子之间的对映选择性(4 + 3)环加成反应,后者是通过烯丙酰胺的氧化而原位生成的。提议使用手性有机磷酰胺抗衡阴离子,通过协同氢键和离子对相互作用参与羟基烯丙基阳离子中间体的活化,从而实现有效的手性转移,从而为最终的加合物提供高非对映和对映选择性。值得注意的是,该反应显示出广泛的底物范围,包括各种取代的烯丙酰胺和呋喃。