Recent advances in metal carbenoid mediated nitrogen-containing zwitterionic intermediate trapping process

Zwitterionic intermediates generated from metal carbenoids and compounds containing enamine units belong to a class of highly active synthetic intermediates that undergo different types of transformations. They can undergo rapid proton transfer to afford C–H functionalization products, or undergo intramolecular trapping process to give [3+2] annulation products. Recently, by taking advantage of its unique electronic feature, novel transformations have been developed by applying suitable electrophiles to trap such type of zwitterionic intermediates. The successful trapping process offers a powerful strategy for the effective construction of diversified nitrogen-containing molecules.