Neutral Aromatic 2,3-Diboranaphthalenes

Incorporating isosteric boron units into aromatic frameworks provides access to molecules with unusual electronic structures and reactivity. We report the synthesis of 2,3-diboranaphthalenes (<b>2</b> and <b>4</b>), the first neutral diboron analogues of naphthalene featuring an <i>o</i>-diborabenzene core. This electron-rich scaffold exhibits pronounced aromaticity and diverse reactivity. Symmetrical <b>2</b> acts as a 6π-aromatic ligand in group 6 metal complexes (<b>5</b>-<b>7</b>) and undergoes double [3 + 2] cycloaddition with CO₂ to afford a fused tetracycle (<b>8</b>). In contrast, unsymmetrical <b>4</b> undergoes electrophile-induced ring contraction (<b>9</b>) and oxidative skeletal editing with selenium (<b>10</b>). These findings establish 2,3-diboranaphthalenes as a new class of neutral boron aromatics, broadening the structural and functional space of main-group aromatic systems.