Pd-Catalyzed Dual C–H Activation/Cyclization: Convergent and Divergent Synthesis of 1-Azahelicenes

Organic Letters, Journal Year: 2024, Volume and Issue: 26(42), P. 9005 - 9010

Published: Oct. 16, 2024

Herein, we report a convergent synthesis of 1-azahelicenes using easily available quinoline derivatives and cyclic diaryliodonium salts as starting materials. This reaction undergoes palladium-catalyzed dual C-H activation/cyclization process to give facile access wide range 1-aza[5]helicenes 1-aza[6]helicenes with abundant functional groups (including F, Cl, Br, I, CF

Language: Английский

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Synthesis of Chiral Substituted meta ‐Bromoanilines as Ligands for Copper-Catalyzed Asymmetric Aldol Addition Reactions

Organic Preparations and Procedures International, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 12

Published: Sept. 9, 2024

Language: Английский

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Additive‐Free Transfer Hydrogenative Direct Asymmetric Reductive Amination Using a Chiral Pyridine‐Derived Half‐Sandwich Catalyst

Angewandte Chemie, Journal Year: 2023, Volume and Issue: 135(31)

Published: June 2, 2023

Abstract Chiral amines are broadly used compounds in pharmaceutical industry and organic synthesis, reductive amination reactions have been the most appreciated methods for their syntheses. However, one‐step transfer hydrogenative direct asymmetric (THDARA) that could expand scope, simplify operation eliminate use of additives has challenging. In this work, based on Xiao's racemic 2010 our recent work novel chiral pyridine ligands, half‐sandwich iridium catalysts were rationally designed synthesized. Using optimized catalyst azeotropic mixture formic acid triethylamine as hydrogen source, a broad range α‐chiral (hetero)aryl amines, including various polar functional groups heterocycles, prepared generally high yield enantioselectivity under mild operationally simple conditions. Density theory (DFT) calculation catalytically active Ir−H species key hydride step supported pyridine‐induced stereospecific generation center, enantioselection by taming highly flexible transition structure with multiple attractive non‐covalent interactions. This introduced type effective simplified approach to medicinally important well rare example robust enantioselective transition‐metal catalysis.

Language: Английский

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Crystallization-Induced Chirality Transfer in Conformationally Flexible Azahelicene Au(I) Complexes with Circularly Polarized Luminescence Activation

Published: Dec. 28, 2023

Flexible and twisted annulated π-systems exhibit numerous unique desirable features owing to their ability display chirality. However, preventing racemization due dynamic nature of chirality remains a challenge. One promising approach stabilize homochirality in such systems is transfer from chiral auxiliary moiety displaying Herein, we introduce new for stabilization conformationally flexible azahelicene species via crystallization-induced intermolecular Au(I) complexes featuring (dibenzo[c,g]carbazole benzo[c]carbazole) enantio-pure N-heterocyclic carbene (NHC) ligands with complementary tailored shape. Crystallization these not only suppresses the diben-zocarbazole species, but also stabilizes through conjunction between NHC dibenzocarbazole ligands. In benzocarbazole complexes, crystals induces initially achiral ligand. Furthermore, crystallization studied activates circularly polarized luminescence (CPL) properties, which were suppressed solution. Importantly, significant CPL enhancement; that feature within crystal structure dissymmetry factors 5 10 times higher than those without transfer.

Language: Английский

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Controlling helicene's pitch by molecular tethering

Organic & Biomolecular Chemistry, Journal Year: 2024, Volume and Issue: 22(7), P. 1365 - 1368

Published: Jan. 1, 2024

We applied post-cyclization annulation to introduce a series of tethered S-shaped double [4]helicenes in which the intramolecular tether imposes specific helical handedness, while length determines helicene's pitch.

Language: Английский

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