As part of our ongoing effort to expand the repertoire of synthetically useful multicomponent reactions (MCRs), we recently disclosed a new synthesis of substituted indoles from nitroalkanes and arylhydrazines in the presence of base. 1 The success of the method relied on transforming the derived nitronate anion 2 (Scheme 1) either to the monoprotonated aci-nitro species 3 or to the di-protonated iminium species 4, with subsequent hydrazine addition and N/N interchange to produce ...
