Syntheses of Millingtonine and Incargranine A Following a Unified Cross-Dimerization-Aromatization Strategy

Millingtonine and incargranine A are alkaloids featuring a tricyclic scaffold consisting of pyrrolidine, tetrahydrofuran, and cyclohexanone. While literature reports two synthons for C₆C₂ units for the installation of enone and aromatic core units in the alkaloids involving multiple steps and expensive reagents, the present strategy depicts a true biosynthetic route using <i>p</i>-quinol as a single C₆C₂ synthon under transition metal-free synthetic routes in four steps. The reaction proceeds via cross-coupling of in situ generated <i>N</i>-aryl enamine with <i>p</i>-quinol, marking a significant advancement in alkaloid synthesis.