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Zhang X, Lu K, Chen X, Su G, Rong X, Ma M. Hydroboration and hydrosilylation of alkenes catalyzed by an unsymmetrical magnesium methyl complex. Org Biomol Chem 2024; 22:5353-5360. [PMID: 38869074 DOI: 10.1039/d4ob00745j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
The hydroboration and hydrosilylation of alkenes catalyzed by the unsymmetrical β-diketiminate magnesium methyl complex [(DippXylNacnac)MgMe (THF)] (1) have been reported. When complex 1 was employed as a highly efficient catalyst in the hydroboration of various alkenes with HBpin, only the anti-Markovnikov hydroboration products were obtained in high yields and with high regioselectivities under mild reaction conditions (60 °C). To our surprise, it showed different regioselectivities in the hydrosilylation of a range of alkenes with PhSiH3. Aromatic alkene substrates afforded the corresponding branched Markovnikov hydrosilylation products in high yields and with high regioselectivities; conversely, aliphatic alkenes produced the linear anti-Markovnikov products in moderate yields. This is completely consistent with the corresponding density functional theory (DFT) calculations. In addition, the practical utility was demonstrated via scale-up reactions of boronate esters and a preliminary plausible mechanism of hydroboration and hydrosilylation have been investigated as well.
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Affiliation(s)
- Xuguang Zhang
- Department of Chemistry and Material Science, College of Science, Nanjing Forestry University, Nanjing 210037, China.
| | - Kai Lu
- Department of Chemistry and Material Science, College of Science, Nanjing Forestry University, Nanjing 210037, China.
| | - Xi Chen
- Department of Chemistry and Material Science, College of Science, Nanjing Forestry University, Nanjing 210037, China.
| | - Guanxin Su
- Department of Chemistry and Material Science, College of Science, Nanjing Forestry University, Nanjing 210037, China.
| | - Xiaofei Rong
- Department of Chemistry and Material Science, College of Science, Nanjing Forestry University, Nanjing 210037, China.
| | - Mengtao Ma
- Department of Chemistry and Material Science, College of Science, Nanjing Forestry University, Nanjing 210037, China.
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Rajput S, Sahoo RK, Sarkar N, Nembenna S. Gallium Hydride-Catalyzed Selective Hydroboration of Unsaturated Organic Substrates. Chempluschem 2024:e202300737. [PMID: 38437065 DOI: 10.1002/cplu.202300737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 03/04/2024] [Accepted: 03/04/2024] [Indexed: 03/06/2024]
Abstract
The first examples of tetrasubstituted conjugated bis-guanidinate (CBG) supported monomeric and thermally stable gallium dihalides [LGaX2], (X=Cl (Ga-Cl), I (Ga-I)) and dihydride (Ga-H) [LGaH2] (where L={(ArHN)(ArN)-C=N-C=(NAr)(NHAr)}; Ar=2,6-Et2-C6H3) compounds are reported. The reaction of in situ generated LLi with 1.0 equiv. GaX3 (X=Cl, I) afforded compounds Ga-Cl and Ga-I. The reaction between Ga-Cl and Li[HBEt3] in benzene yielded the dihydride compound Ga-H. All reported compounds (Ga-Cl, Ga-I, and Ga-H) were characterized by NMR, HRMS, and single-crystal X-ray diffraction studies. Ga-H was probed for the hydroboration of carbodiimides (CDI), isocyanates, and isothiocyanates with HBpin. Compound Ga-H was also found effective for the catalytic hydroboration of imines, nitriles, alkynes, esters, and formates, affording the corresponding products in quantitative yields. Stoichiometric reactions with a CDI were performed to establish the catalytic cycle.
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Affiliation(s)
- Sagrika Rajput
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), Homi Bhabha National Institute (HBNI), Bhubaneswar, 752050, India
| | - Rajata Kumar Sahoo
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), Homi Bhabha National Institute (HBNI), Bhubaneswar, 752050, India
| | - Nabin Sarkar
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), Homi Bhabha National Institute (HBNI), Bhubaneswar, 752050, India
| | - Sharanappa Nembenna
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), Homi Bhabha National Institute (HBNI), Bhubaneswar, 752050, India
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3
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Kumar R, Mahata B, Gayathridevi S, Vipin Raj K, Vanka K, Sen SS. Lanthanide Mimicking by Magnesium for Oxazolidinone Synthesis. Chemistry 2024; 30:e202303478. [PMID: 37897110 DOI: 10.1002/chem.202303478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 10/26/2023] [Accepted: 10/27/2023] [Indexed: 10/29/2023]
Abstract
In the last decade, magnesium complexes have emerged as a viable alternative to transition-metal catalysts for the hydrofunctionalization of unsaturated bonds. However, their potential for advanced catalytic reactions has not been thoroughly investigated. To address this gap, we have developed a novel magnesium amide compound (3) using a PNP framework that is both bulky and flexible. Our research demonstrates that compound 3 can effectively catalyze the synthesis of biologically significant oxazolidinone derivatives. This synthesis involves a tandem reaction of hydroalkoxylation and cyclohydroamination of isocyanate using propargyl alcohol. Furthermore, we conducted comprehensive theoretical calculations to gain insights into the reaction mechanism. It is important to note that these types of transformations have not been reported for magnesium and would significantly enhance the catalytic portfolio of the 7th most abundant element.
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Affiliation(s)
- Rohit Kumar
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Biplab Mahata
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - S Gayathridevi
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - K Vipin Raj
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Kumar Vanka
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Sakya S Sen
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
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4
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Janda BA, Tran JA, Chang DK, Nerhood GC, Maduka Ogba O, Liberman-Martin AL. Carbodiimide and Isocyanate Hydroboration by a Cyclic Carbodiphosphorane Catalyst. Chemistry 2024; 30:e202303095. [PMID: 37847813 DOI: 10.1002/chem.202303095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 10/13/2023] [Accepted: 10/17/2023] [Indexed: 10/19/2023]
Abstract
We report hydroboration of carbodiimide and isocyanate substrates catalyzed by a cyclic carbodiphosphorane catalyst. The cyclic carbodiphosphorane outperformed the other Lewis basic carbon species tested, including other zerovalent carbon compounds, phosphorus ylides, an N-heterocyclic carbene, and an N-heterocyclic olefin. Hydroborations of seven carbodiimides and nine isocyanates were performed at room temperature to form N-boryl formamidine and N-boryl formamide products. Intermolecular competition experiments demonstrated the selective hydroboration of alkyl isocyanates over carbodiimide and ketone substrates. DFT calculations support a proposed mechanism involving activation of pinacolborane by the carbodiphosphorane catalyst, followed by hydride transfer and B-N bond formation.
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Affiliation(s)
- Ben A Janda
- Chemistry and Biochemistry Program, Schmid College of Science and Technology, Chapman University, 450 North Center Street, Orange, CA 92866, USA
| | - Julie A Tran
- Chemistry and Biochemistry Program, Schmid College of Science and Technology, Chapman University, 450 North Center Street, Orange, CA 92866, USA
| | - Daniel K Chang
- Chemistry and Biochemistry Program, Schmid College of Science and Technology, Chapman University, 450 North Center Street, Orange, CA 92866, USA
| | - Gabriela C Nerhood
- Chemistry and Biochemistry Program, Schmid College of Science and Technology, Chapman University, 450 North Center Street, Orange, CA 92866, USA
| | - O Maduka Ogba
- Chemistry and Biochemistry Program, Schmid College of Science and Technology, Chapman University, 450 North Center Street, Orange, CA 92866, USA
| | - Allegra L Liberman-Martin
- Chemistry and Biochemistry Program, Schmid College of Science and Technology, Chapman University, 450 North Center Street, Orange, CA 92866, USA
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