Bench-Stable Meisenheimer\nComplexes: Synthesis, Characterization,\nand Divergent Reactivity for Dearomatization

The chemistry of the Meisenheimer complexes is of fundamental\ninterest\nin organic chemistry. While the nitro group has been extensively employed\nto facilitate the formation and stabilization of Meisenheimer complexes,\nthe analogous application of more user-friendly ester groups has remained\nan unexplored frontier. Herein, we report ester-stabilized Meisenheimer\ncomplexes, which have remarkable air-, moisture-, and thermo-stability.\nMoreover, the isolable and well-defined Meisenheimer intermediates\nexhibit divergent reactivity for dearomatization reactions, including\nmodular 1,4-additions, dearomative (2 + 3) cycloadditions, and even\nhigher-order (4 + <i>n</i>) cycloadditions. These methodologies\nenabled rapid access to complicated cyclohexane derivatives with multiple\nall-carbon quaternary centers and interesting structure topologies.