Abstract The formal cycloaddition of α-metallated methyl isocyanides 1 onto the triple bond of electron-deficient acetylenes 2 represents a direct and convenient approach to oligosubstituted pyrroles 3. The scope and limitations of this reaction (24 examples, 25–97% yield) are reported along with an optimization of the reaction conditions and a rationalization of the mechanism. In addition, a related newly developed Cu I-mediated synthesis of 2, 3- ...
