Chiral Fjord‐Edged Nanographenes Constructed by Allylic‐Migration‐Mediated Cyclization

ABSTRACT Fjord‐edged nanographenes (NGs) with non‐planar π‐conjugated frameworks and intrinsic chirality are attractive for nonlinear optics and chiroptical applications. However, synthetic routes to these highly twisted NGs remain elusive, largely restricted to Scholl‐type cyclization, which typically requires bulky substituents to prevent over‐dehydrogenation into conventional armchair edge structures. Here we report an allylic‐migration‐mediated cyclization strategy for the construction of fjord‐edged NGs. In this strategy, a first allylic migration drives an intramolecular cyclization that pre‐installs the fjord region. A second migration then enables a subsequent cyclization, and the final selective dehydrogenation completes the aromatization while preserving the fjord‐edged topology. DFT calculations support the essential role of each migration in enabling the corresponding cyclization. Using this strategy, we successfully synthesized fjord‐edged NGs 1 and 2 , built on chrysene and bischrysene cores, respectively. Their structures are unambiguously confirmed by single‐crystal X‐ray diffraction. Notably, 2 exhibits near‐infrared (NIR) emission extending into the NIR‐II region. Despite the absence of substituents at the fjord region, both compounds possess high racemization barriers and are readily resolved into pure enantiomers by chiral HPLC. It is remarkable that 2 exhibits an exceptional dissymmetry factor (| g abs | = 2.5 × 10 −2 ), exceeding those of pristine [5]helicene and previously reported fjord‐edged NGs.