Modular Dearomative 1,4-Addition to Simple Arenes with Dual Nucleophiles: Overriding the Inherent 1,2-Selectivity via η6-Coordination.

Functionalized 1,4-cyclohexadienes are valuable synthetic intermediates, yet their direct assembly from arene feedstocks via dearomative 1,4-addition remains a daunting challenge. Among arene dearomatization strategies, η6-coordination chemistry has long been used but invariably delivers 1,2-adducts due to an inherent regiochemical bias. Herein, we report the first intermolecular dearomative 1,4-addition to simple, unactivated arenes using dual nucleophiles via η6-coordination to chromium/molybdenum. By employing a labile iodine placeholder that blocks the inner-sphere reductive elimination, we override the innate 1,2-selectivity, enabling both dearomative 1,4-dialkylation and 1,4-hydroalkylation. The method features an extraordinarily broad arene scope, excellent functional-group tolerance, and predictable regioselectivity. Isolation of a key Mo(II)-I intermediate with single-crystal X-ray diffraction and sufficient control experiments supports the proposed outer-sphere pathway. Synthetic utility is well demonstrated by site-selective dearomatization within polyaromatics, late-stage drug modification, and total synthesis of alkaloids.