Chromium Mediated Reductive Coupling of Isonitrile Forms Unusual Heterocycles

The quintuply bonded α-diimine chromium dimer [HLiPrCr]2 reductively couples cyclohexyl isocyanide to produce various novel nitrogen heterocycles. Tetramerization yielded, inter alia, the aromatic squaramidinate, i.e. [C4(NCy)4]2–, whereas hexamerization produces a substituted 1,4-diaza-bicyclo[3.3.0]­octadiene dianion. These unprecedented transformations complement the coupling reactions of isoelectronic CO, and they may prove synthetically useful.五重键合α-二亚胺铬二聚体[HLiPrCr]₂可通过还原偶联环己基异氰化物，生成多种新型氮杂环化合物。四聚反应除生成其他产物外，还得到芳香族方酰胺类物种，即[C₄(NCy)₄]²⁻；六聚反应则生成取代的1,4-二氮杂双环[3.3.0]辛二烯二阴离子。这些前所未有的转化过程与等电子体一氧化碳的偶联反应形成互补，在合成化学领域具备潜在应用价值。