Metal-free assembly of diverse polysubstituted pyridines via an efficient cascade approach using tertiary enaminones and ,-unsaturated sulfonylketimines

Herein, we report a metal-free, scalable, and cascade protocol for constructing polysubstituted pyridines from N,N-dimethyl enaminones and alpha,beta-unsaturated sulfonylketimines by cleaving C-N/N-S bonds. This efficient methodology (up to 96% yield) assembles multi-substituted pyridines, including those containing pharmacologically important cores, via cycloaddition rather than a radical pathway. Significantly, this is a rare example of rapidly forming polysubstituted pyridines under metal-free conditions through C-N/N-S bond cleavage of tertiary enaminones.