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Electrochemical synthesis of heterodehydro[7]helicenes.

ABSTRACT: Dehydrohelicenes are some of the most attractive chiroptical materials with unique helical chirality. However, to our knowledge, there are no prior reports on their direct construction by asymmetric methods. In this work, sequential synthesis of aza-oxa-dehydro[7]helicenes via the electrochemical oxidative hetero-coupling of 3-hydoxycarbazoles and 2-naphthols followed by dehydrative cyclization and intramolecular C-C bond formation has been realized. In addition, an efficient enantioselective synthesis through chiral vanadium-catalyzed hetero-coupling and electrochemical oxidative transformations afforded heterodehydro[7]helicene without any racemization. The obtained dehydro[7]helicenes showed intense blue-colored circularly polarized luminescence (|g_lum| ≈ 2.5 × 10^-3 at 433 nm). Thermodynamic and kinetic studies of the racemization barrier of heterodehydro[7]helicenes indicated significant chiral stability with ΔG^‡> 140 kJ mol^-1.

SUBMITTER: Khalid MI

PROVIDER: S-EPMC9814689 | biostudies-literature | 2022 Dec

REPOSITORIES: biostudies-literature

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Electrochemical synthesis of heterodehydro[7]helicenes.

Khalid Md Imrul MI Salem Mohamed S H MSH Sako Makoto M Kondo Masaru M Sasai Hiroaki H Takizawa Shinobu S

Communications chemistry 20221203 1

Dehydrohelicenes are some of the most attractive chiroptical materials with unique helical chirality. However, to our knowledge, there are no prior reports on their direct construction by asymmetric methods. In this work, sequential synthesis of aza-oxa-dehydro[7]helicenes via the electrochemical oxidative hetero-coupling of 3-hydoxycarbazoles and 2-naphthols followed by dehydrative cyclization and intramolecular C-C bond formation has been realized. In addition, an efficient enantioselective sy ...[more]

PMID: 36697698

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