coordination diastereomer according to their NMR spectra (−5 to −20 °C). This stereoselective coordination results in stereoselective electrophilic addition at the uncoordinated β carbon (C3) when the complexes are treated with trifluoromethanesulfonic acid (HOTf), methyl triflate, or dimethoxymethane. These stereoselective reactions at C3 are a direct result of differentiation of the pyrrole enantiofaces
一系列的不对称ñ -取代
吡咯(1 - 7)已经从
氨基酸衍
生物合成和络合到pentaammineosmium(II)片段。许多这些
吡咯络合物(的8 - 14)示出了用于一个非对映体协调热力学优选根据它们的NMR谱(-5至-20℃)。当用三
氟甲烷磺酸(HOTf),三
氟甲磺酸甲酯或二甲氧基
甲烷处理络合物时,这种立体选择性配位导致在未配位的β碳(C3)处发生立体选择性亲电子加成。在C3处的这些立体选择性反应是
吡咯对映体分化的直接结果。