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Updated: Oct 7, 2025

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Published on: June 21, 2017
Modulating the Frontier Orbitals of an Aluminylene for Facile Dearomatization of Inert Arenes
1Department of Chemistry and Shenzhen Grubbs Institute, Southern University of Science and Technology, Shenzhen, 518055, China.
Abstract:
Lewis bases are well known to stabilize electron-deficient species. We demonstrate herein that the redox property of a monocoordinated aluminylene 1 featuring only four valence electrons for the shell of Al can be boosted by a Lewis base. The coordination of 1 with an N-heterocyclic carbene (NHC) effectively shrinks the HOMO-LUMO gap, thereby enhancing the reactivity of the ensuing acyclic mono-NHC-stabilized aluminylene 2, which is isoelectronic with singlet carbenes. Moreover, such base coordination completely reverses the predominant chemical reactivity (i.e. electrophilicity/nucleophilicity) of aluminylenes. In marked contrast to 1, 2 readily undergoes a [4+1] cycloaddition reaction with naphthalene and biphenylene at room temperature. Strikingly, the enhanced ambiphilic nature of Al in 2 also enables facile cleavage of aromatic C-C bonds of inert arenes in both intra- and intermolecular fashion affording 3 and 5. The formation of 5 represents the first example of the cleavage of an aromatic C(3)-C(4) bond in biphenylene by a single-atom center.
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