Electron deficient 5-hydroxy-1,2-dihydroisoquinolin-1-ones – A new class of fluorescent dyes with large Stokes shifts

Cascade Vinylation/8π-Electrocyclization and Cu(II)-Catalyzed Dehydrogenation toward Highly Stable Formally Antiaromatic Cycloheptatrienyl Anions

“…It is also viable that the distortion of a seven-membered ring in HMCH is caused by steric hindrance of ester groups which can be disabled in the case of less sterically hindered substituents. Moreover, HMCH was found to exhibit unique reactivity under the action of various nucleophilic and electrophilic agents, yielding a number of functional materials with interesting properties, for example, large Stokes shift superphotoacidic fluorophores. − On the other hand, we have shown that other available cycloheptatrienes containing up to five electron-withdrawing groups neither form a stable anion nor exhibit chemical properties of HMCH . Thus, a new strategy for the synthesis of highly electron-deficient cycloheptatrienes will be of high demand from both theoretical and applicative points of view.…”

The Antiaromatic Nucleophilic Substitution Reaction (SNAAr) in Cycloheptatrienyl-Anion Containing Zwitterions with a Möbius-Aromatic Intermediate

“…Moreover, we have observed a nucleophilic attack onto an electron-deficient cycloheptatrienyl-anion system in potassium hepta(metoxycarbonyl)cycloheptatrienide. 8,9,19 However, in this case the atom attached to the pyridinium ring is sterically unavailable whereas a nucleophilic addition to a more sterically available atom joint to an ester group is not likely to afford the products. Therefore, we propose an elimination/addition mechanism for the substitution reactions, although it is unusual for vinylic compounds, (Scheme 2).…”

“…1 Notably, our previous works highlighted the reactivity of stable hepta-(methoxycarbonyl)cycloheptatrienyl potassium toward both electrophilic 2−5 and nucleophilic 6,7 reagents, particularly amines, leading to the formation of fluorescent 5-hydroxyisoquinolones with significant Stokes shifts due to superphotoacidity (excited-state proton transfer to solvent). 8,9 While such reactive cycloheptatrienes were previously limited to hepta(methoxycarbonyl)cycloheptatriene, our recent studies have expanded this repertoire to include seven stable cycloheptatrienyl-anion containing compounds. 10−12 In this manuscript, we introduce a novel approach for substituting groups attached to a cycloheptatrienyl-anion core.…”

Cyсlopentadienone and Pyrone Derivatives as Precursors of Electron-Deficient Cycloheptatrienes: Quantum Chemical Investigation and Synthesis

“…In particular, unlike parent cycloheptatriene that forms electrophilic tropylium cation 1,2 electron-deficient cycloheptatrienes [3][4][5] form stable cycloheptatrienides, 5 reacting with both nucleophilic and electrophilic species to form various carbo-and heterocyclic compounds. 1,[6][7][8][9][10] There are only several general methods for the synthesis of such cycloheptatrienes. Previously, we have extensively investigated [11][12][13][14] the scope of the cascade assemble of electron-defficient cycloheptatriene derivatives from simple molecules with an electrocyclic ring-closure 15,16 at the late stages.…”

“…In particular, unlike parent cycloheptatriene that forms electrophilic tropylium cation 1 2 electron-deficient cycloheptatrienes 3–5 form stable cycloheptatrienides, 5 reacting with both nucleophilic and electrophilic species to form various carbo- and heterocyclic compounds. 1 , 6 7 8 9 10…”