Polarity on Demand: Nucleophilic, Electrophilic, and Ambiphilic Reactivity at a 9,10‐Dihydro‐9,10‐Disilaanthracene Platform

ABSTRACT 9,10‐Dihydro‐9,10‐diheteroanthracenes constitute rigid molecular entities that enable cooperative reactivity between two proximal heteroatoms. While diboraanthracenes act as ditopic Lewis acids and diphosphaanthracenes as ditopic Lewis bases, ambiphilic behavior has so far largely relied on the incorporation of two different heteroelements. Herein, we demonstrate ambiphilicity within a homo‐heteroelement framework based on 9,10‐dihydro‐9,10‐disilaanthracene (DSA). Efficient cyclocondensation of 1,2‐disilyl‐4,5‐dimethylbenzene, promoted by substoichiometric amounts of MeLi, affords DSA 1 2H featuring two SiH 2 groups. Compound 1 2H exhibits electrophilic reactivity toward magnesium anthracene, affording a double ‘butterfly’‐type framework 13 reminiscent of the anthracene photodimer. Selective reductive Si–H bond cleavage using 2 equiv. KC 8 or excess elemental K enables controlled, stepwise access to the monosilanide [ 1 H ] − or the disilanide [ 1 ] 2− , respectively. The disilanide [ 1 ] 2− , which was structurally characterized by SCXRD, behaves as a ditopic Lewis base toward 9,10‐dihydro‐9,10‐diboraanthracene, forming a cyclic, 13 ‐type double adduct K 2 [ 10 ]. Notably, [ 1 H ] − displays ambiphilic reactivity toward p TolC≡C p Tol to furnish a tricyclic product containing a deprotonated 1,2‐ethylenediyl bridge between the Si centers. These findings establish that controlled reduction within a homo‐heteroelement platform enables polarity switching, thereby providing a versatile strategy for the design of cooperative main‐group reactivity.