enantioselective [4 + 2] annulation of 2-ylideneoxindole with malononitrile has been accomplished by cinchonine catalysis under mild conditions. The corresponding enantiomerically enriched 4H-pyrano[3,2-b]indoles were generated in moderate to high yields (up to 94%) with excellent enantioselectivities (up to 98% ee). To explain the stereoselectivity of the organocatalytic Michael-ammonization cascade, we
通过在温和条件下用
辛可宁催化,可以实现2-亚硝基新
吲哚与
丙二腈的高度对映选择性[4 + 2]环化反应。相应的对映体富集的4 H-
吡喃并[3,2- b ]
吲哚以中等至高收率(高达94%)和优异的对映选择性(高达98%ee)生成。为了解释有机催化迈克尔-
氨化级联反应的立体选择性,我们还进行了控制实验,并基于观察到的产物立体
化学,提出了催化循环的合理过渡态模型。此外,某些产品在体外对
金黄色葡萄球菌和表皮葡萄球菌具有中等程度的抗菌活性。,这可能被视为发现新的抗菌剂的潜在线索。