The reaction of o,o′-dialkyl-substituted aryl isonitriles with N-propargyl-6-iodopyridones provides 11H-indolizino[1,2-b]quinolin-9-ones with significant regioselectivity in favor of the more crowded product. The usefulness of the method is illustrated with a regioselective synthesis of (20S)-7-trimethylsilyl-9-isopropyl camptothecin.
o,o'-二烷基取代的芳基异腈与 N-propargyl-6-iodopyridones 的反应提供了具有显着区域选择性的 11H-indolizino[1,2-b]quinolin-9-ones,有利于更拥挤的产物。该方法的有用性通过 (20S)-7-三甲基甲
硅烷基-9-异丙基
喜树碱的区域选择性合成来说明。