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Zacharias H, Begum A, Han J, Bartholome TA, Marder TB, Martin CD. Synthesis of phenanthrylboroles and formal nitrene insertion to access azaborapyrenes. Chem Commun (Camb) 2024. [PMID: 39072482 DOI: 10.1039/d4cc02863e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Extended conjugation has been introduced into boroles but only on the 2,3- or 4,5-positions of the central BC4 core. In this work we synthesize phenanthrylboroles that also have conjugation on the 3,4-positions and demonstrate their insertion reactivity with azides to furnish B,N-analogues of pyrene.
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Affiliation(s)
- Harie Zacharias
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, USA.
| | - Ayesha Begum
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, USA.
| | - Jianhua Han
- Institut für Anorganische Chemie, and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Tyler A Bartholome
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, USA.
| | - Todd B Marder
- Institut für Anorganische Chemie, and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Caleb D Martin
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, USA.
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Lamprecht A, Arrowsmith M, Dietz M, Fuchs S, Rempel A, Härterich M, Braunschweig H. Synthesis, reduction and C-H activation chemistry of azaborinines with redox-active organoboryl substituents. Dalton Trans 2024; 53:1004-1013. [PMID: 38088750 DOI: 10.1039/d3dt03826b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
The 2,3,4,5,6-pentaphenyl-1,2-azaborinin-1-yl (PPAB) potassium complex 1 undergoes facile salt metathesis with 9,10-dibromo-9,10-dihydroboraanthracene (DBABr2), 5-bromodibenzo[b,d]borole (DBBBr), 1-chlorotetraphenylborole (TPBCl) and dibromo(phenyl)borane (BBr2Ph) to yield the corresponding N-borylated azaborinines N-DBABr-PPAB (2, which hydrolyses and dimerises to the oxo-bridged N,N'-O(DBA)2-(PPAB)2, 3), N,N'-DBA-(PPAB)2 (4), N-DBB-PPAB (5), N-PPB-PPAB (7) and N-BBrPh-PPBA (9). Stepwise reduction of 4 yields the corresponding stable radical anion 4˙- and dianion 42-. One-electron reduction of 5 with KC8 yields the purple radical anion 5˙-, which forms a highly insoluble coordination polymer. 5˙- undergoes very slow radical intramolecular ortho-C-H activation at the C4-phenyl substituent of the PPAB moiety, yielding a BN-analogue of the 5,5'-spiro-bi[dibenzoborole] anion, [6]K. Compound 7 cannot be isolated and undergoes spontaneous and diastereoselective 2,5-anti-addition of the ortho-C-H bond of the PPAB C4-phenyl substituent to yield a novel BNB-analogue of the triply fused dihydrocyclopenta[l]phenanthrene cation, compound 8. Finally the one-electron reduction of 9 results in the ortho-C-H activation of the PPAB C4-phenyl substituent at an in situ-generated dicoordinate boryl anion (10), resulting in the formation of a BNB-analogue of 9H-fluorene, the borate 11-. DFT calculations provide a rationale for the diverse C-H activations observed in these reactions.
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Affiliation(s)
- Anna Lamprecht
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Merle Arrowsmith
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Maximilian Dietz
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Sonja Fuchs
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Anna Rempel
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Marcel Härterich
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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