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Li X, Song Q. "Homoleptic" Tetracoordinate Boron Compounds. Inorg Chem 2024; 63:5295-5314. [PMID: 38488071 DOI: 10.1021/acs.inorgchem.4c00102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
"Homoleptic" tetracoordinate boron compounds, in which the central boron atom links to four identical atoms, are a special and important family of boron compounds. During the past decades, they have been extensively employed in inorganic, organic, macromolecular, and materials chemistry. Many of them exhibit a diverse range of outstanding properties, and therefore, the synthesis and application of those compounds have emerged as a hot research topic in modern boron chemistry. This review summarizes and discusses the "homoleptic" tetracoordinate boron compounds, which are organized according to the kinds of atoms coordinated to the central boron.
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Affiliation(s)
- Xin Li
- Institute of Next Generation Matter Transformation, College of Materials Science & Engineering, Huaqiao University, Xiamen, Fujian 361021, China
| | - Qiuling Song
- Key Laboratory of Molecule Synthesis and Function Discovery, Fujian Province University, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China
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Osminski WEG, Lu Z, Zhao W, Mohammadlou A, Yin X, Matthews EC, Canestraight VM, Staples RJ, Allen CJ, Hirschi JS, Wulff WD. Probing Catalyst Function - Electronic Modulation of Chiral Polyborate Anionic Catalysts. J Org Chem 2021; 86:17762-17773. [PMID: 34852456 DOI: 10.1021/acs.joc.1c01769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Boroxinate complexes of VAPOL and VANOL are a chiral anionic platform that can serve as a versatile staging arena for asymmetric catalysis. The structural underpinning of the platform is a chiral polyborate core that covalently links together alcohols (or phenols) and vaulted biaryl ligands. The polyborate platform is assembled in situ by the substrate of the reaction, and thus a multiplex of chiral catalysts can be rapidly assembled from various alcohols (or phenols) and bis-phenol ligands for screening of catalyst activity. In the present study, variations in the steric and electronic properties of the phenol/alcohol component of the boroxinate catalyst are probed to reveal their effects on the asymmetric induction in the catalytic asymmetric aziridination reaction. A Hammett study is consistent with a mechanism in which the two substrates are hydrogen-bonded to the boroxinate core in the enantiogenic step. The results of the Hammett study are supported by a computational study in which it is found that the H-O distance of the protonated imine hydrogen bonded to the anionic boroxinate core decreases with an increase in the electron releasing ability of the phenol unit incorporated into the boroxinate. The results are not consistent with a mechanism in which the boroxinate catalyst functions as a Lewis acid and activates the imine by a Lewis acid/Lewis base interaction.
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Affiliation(s)
- Wynter E G Osminski
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Zhenjie Lu
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Wenjun Zhao
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Aliakbar Mohammadlou
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Xiaopeng Yin
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Emily C Matthews
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Virginia M Canestraight
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Richard J Staples
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Connor J Allen
- Department of Chemistry, Binghamton University, Binghamton, New York 13902, United States
| | - Jennifer S Hirschi
- Department of Chemistry, Binghamton University, Binghamton, New York 13902, United States
| | - William D Wulff
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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