Since the seminal work of Zhang in
2016, donor–acceptor
cyanoarene-based fluorophores, such as 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene
(4CzIPN), have been widely applied in photoredox catalysis and used
as excellent metal-free alternatives to noble metal Ir- and Ru-based
photocatalysts. However, all the reported photoredox reactions involving
this chromophore family are based on harnessing the energy from a
single visible light photon, with a limited range of redox potentials
from −1.92 to +1.79 V vs SCE. Here, we document the unprecedented
discovery that this family of fluorophores can undergo consecutive
photoinduced electron transfer (ConPET) to achieve very high reduction
potentials. One of the newly synthesized catalysts, 2,4,5-tri(9H-carbazol-9-yl)-6-(ethyl(phenyl)amino)isophthalonitrile
(3CzEPAIPN), possesses a long-lived (12.95 ns) excited radical anion
form, 3CzEPAIPN•–*, which can be used to
activate reductively recalcitrant aryl chlorides (E
red ≈ −1.9 to −2.9 V vs SCE) under
mild conditions. The resultant aryl radicals can be engaged in synthetically
valuable aromatic C–B, C–P, and C–C bond formation
to furnish arylboronates, arylphosphonium salts, arylphosphonates,
and spirocyclic cyclohexadienes.
Deuterated organic compounds have widespread applications in many fields such as medicinal chemistry, mechanistic studies, and quantitative analyses. Traditionally, the incorporation of deuterium atom into organic compounds can be achieved...
A synergistic combination of photoredox and polarity reversal catalysis enabled a hydrogen evolution cross-coupling of silanes with H2O, alcohols, phenols, and silanols, which afforded the corresponding silanols, monosilyl ethers, and...
A novel
P(NMe2)3-mediated tandem (1 + 4)
annulation between aroylformates and δ-tosylamino enones has
been developed that affords a facile synthesis of functionalized pyrrolidines
in moderate to excellent yields with exclusive chemoselectivity and
high diastereoselectivity. Mechanistic investigation reveals that
the reaction proceeds through an unprecedented P(NMe2)3-mediated reductive amination/base-catalyzed Michael addition
cascade. The reaction herein also represents the first study of the
reactivity patterns of the Kukhtin–Ramirez adducts toward ambiphilic
nucleophile–electrophiles.
The reactivity patterns of the modified Huisgen zwitterions derived from arylazocarboxylates toward 1,2-dicarbonyl compounds have been studied for the first time for a facile synthesis of N-aryl–N-acyl hydrazones.
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