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Zhang X, Yang S, Zeng X. Ring Contraction by Rearrangement of Sterically Congested Cyclic (Amino)(aryl)carbenes. J Org Chem 2024. [PMID: 38808612 DOI: 10.1021/acs.joc.4c00466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
The rearrangement of sterically congested cyclic (amino)(aryl)carbenes (CAArCs) by the reaction of related iminium salts with potassium bis(trimethylsilyl)amide is reported, allowing for forming benzocyclobutanimines via a ring contraction process. Mechanistic studies by theoretical calculations indicate that the formation of conjugated ketenimines as intermediates could be considered, in which steric hindrance caused by N-alkyl motifs of CAArCs plays an important role in promoting the ring-opening by the cleavage of C-N bond.
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Affiliation(s)
- Xiaoyu Zhang
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Shangru Yang
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Xiaoming Zeng
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
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2
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Wang X, Zhong J, Luo M, Zeng X. Cr-Catalyzed Intramolecular Arylative Cross-Coupling of Unactivated C-H Bonds with C-Halide Bonds. Org Lett 2024; 26:4093-4097. [PMID: 38717255 DOI: 10.1021/acs.orglett.4c01145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
We report here a chromium-catalyzed intramolecular arylation of unactivated C-H bonds with C-halide bonds under mild conditions. This reaction was enabled by using a low-cost CrCl2 salt as the precatalyst in combination with allylmagnesium bromide and E/Z-mixed 1-halo-2-styrylarenes as substates, providing a strategy for the construction of functionalized phenanthrene compounds without using external ligands.
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Affiliation(s)
- Xuelan Wang
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China
| | - Jiaoyue Zhong
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China
| | - Meiming Luo
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China
| | - Xiaoming Zeng
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China
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3
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Liu S, Luo Z, Zhao S, Luo M, Zeng X. Cr-catalyzed borylation of C(aryl)-F bonds using a terpyridine ligand. Chem Commun (Camb) 2024; 60:5201-5204. [PMID: 38651837 DOI: 10.1039/d4cc01330a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
The defluoroborylation of fluoroarenes by chromium-catalyzed cleavage of unactivated C-F bonds is described. The reaction uses HBpin as the boron source, low-cost and commercially available chromium salt as the precatalyst, and terpyridine as a crucial ligand, providing a protocol with atom-efficient benefits and a wide range of applicable substrates for the functionalization of aryl C-F bonds. Preliminary mechanistic studies indicate that an unprecedented Cr-catalyzed magnesiation of the unactivated C-F bond occurred. The generated arylmagnesium intermediates then participated in the subsequent borylation reaction. The application of the strategy in the preparation of valuable derivatives is demonstrated by the late-stage functionalization of boronate ester groups.
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Affiliation(s)
- Senlin Liu
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China.
| | - Zheng Luo
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China.
| | - Shuaiyong Zhao
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China.
| | - Meiming Luo
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China.
| | - Xiaoming Zeng
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China.
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4
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Ajayi T, Lough AJ, Morris RH. Mechanochemical Synthesis of Chromium(III) Complexes Containing Bidentate PN and Tridentate P-NH-P and P-NH-P' Ligands. ACS OMEGA 2024; 9:19690-19699. [PMID: 38708235 PMCID: PMC11064035 DOI: 10.1021/acsomega.4c02076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Revised: 04/02/2024] [Accepted: 04/05/2024] [Indexed: 05/07/2024]
Abstract
Chromium(III) complexes bearing bidentate {NH2(CH2)2PPh2: PN, (S,S)-[NH2(CHPh)2PPh2]: P'N} and tridentate [Ph2P(CH2)2N(H)(CH2)2PPh2: P-NH-P, (S,S)-(iPr)2PCH2CH2N(H)CH(Ph)CH(Ph)PPh2: P-NH-P'] ligands have been synthesized using a mechanochemical approach. The complexes {cis-[Cr(PN)Cl2]Cl (1), cis-[Cr(P'N)Cl2]Cl (2), mer-Cr(P-NH-P)Cl3 (3), and mer-Cr(P-NH-P')Cl3 (4)} were obtained in high yield (95-97%) via the grinding of the respective ligands andthe solid Cr(III) ion precursor [CrCl3(THF)3] with the aid of a pestle and mortar, followed by recrystallization in acetonitrile. The isolated complexes are high spin. A single-crystal X-ray diffraction study of 2 revealed a cationic chromium complex with two P'N ligands in a cis configuration with P' trans to P' with chloride as the counteranion. The X-ray study of 4 shows a neutral Cr(III) complex with the P-NH-P' ligand in a mer configuration. The difference in molecular structures and bulkiness of the ligands influence the electronic, magnetic, and electrochemical properties of the complexes as exhibited by the bathochromic shifts in the electronic absorption peaks of the complexes and the relative increase in the magnetic moment of 3 (4.19 μβ) and 4 (4.15 μβ) above the spin only value (3.88 μβ) for a d3 electronic configuration. Complexes 1-4 were found to be inactive in the hydrogenation of an aldimine [(E)-1-(4-fluorophenyl)-N-phenylmethanimine] under a variety of activating conditions. The addition of magnesium and trimethylsilyl chloride in THF did cause hydrogenation at room temperature, but this occurred even in the absence of the chromium complex. The hydrogen in the amine product came from the THF solvent in this novel reaction, as determined by deuterium incorporation into the product when deuterated THF was used.
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Affiliation(s)
- Tomilola
J. Ajayi
- Department of Chemistry, University
of Toronto, 80 Saint George Street, Toronto M5S3H6, Ontario, Canada
| | - Alan J. Lough
- Department of Chemistry, University
of Toronto, 80 Saint George Street, Toronto M5S3H6, Ontario, Canada
| | - Robert H. Morris
- Department of Chemistry, University
of Toronto, 80 Saint George Street, Toronto M5S3H6, Ontario, Canada
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5
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Zhong J, Wang X, Luo M, Zeng X. Chromium-Catalyzed Alkene Isomerization with Switchable Selectivity. Org Lett 2024; 26:3124-3129. [PMID: 38592221 DOI: 10.1021/acs.orglett.4c00737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
We report a single additive-responsive chromium-catalyzed system for selectively producing either of two different internal alkene isomers. The chromium catalyst, in the presence of HBpin/LiOtBu, enables the isomerization of alkenes over multiple carbon atoms to give the most thermodynamically stable isomers. The same catalyst allows for the selective isomerization of terminal alkenes over one carbon atom without an additive, exhibiting efficient and controllable alkene transposition selectivity.
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Affiliation(s)
- Jiaoyue Zhong
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China
| | - Xuelan Wang
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China
| | - Meiming Luo
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China
| | - Xiaoming Zeng
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China
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6
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Sk M, Haldar S, Bera S, Banerjee D. Recent advances in the selective semi-hydrogenation of alkyne to ( E)-olefins. Chem Commun (Camb) 2024; 60:1517-1533. [PMID: 38251772 DOI: 10.1039/d3cc05395d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
Considering the potential importance and upsurge in demand, the selective semi-hydrogenation of alkynes to (E)-olefins has attracted significant interest. This article highlights the recent advances in newer technologies and important methodologies directed to (E)-olefins from alkynes developed from 2015 to 2023. Notable features summarised include the catalyst or ligand design and control of product selectivity based on precious and nonprecious metal catalysts for semi-hydrogenation to (E)-olefins. Mechanistic studies for various catalytic transformations, including synthetic application to bioactive compounds, are summarised.
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Affiliation(s)
- Motahar Sk
- Department of Chemistry, Laboratory of Catalysis and Organic Synthesis Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India.
| | - Shuvojit Haldar
- Department of Chemistry, Laboratory of Catalysis and Organic Synthesis Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India.
| | - Sourajit Bera
- Department of Chemistry, Laboratory of Catalysis and Organic Synthesis Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India.
| | - Debasis Banerjee
- Department of Chemistry, Laboratory of Catalysis and Organic Synthesis Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India.
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7
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Meng Y, Zare RN, Gnanamani E. Superfast Formation of C(sp 2 )-N, C(sp 2 )-P, and C(sp 2 )-S Vinylic Bonds in Water Microdroplets. Angew Chem Int Ed Engl 2024; 63:e202316131. [PMID: 38116872 DOI: 10.1002/anie.202316131] [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: 10/24/2023] [Revised: 12/14/2023] [Accepted: 12/18/2023] [Indexed: 12/21/2023]
Abstract
We report examples of C(sp2 )-N, C(sp2 )-S, and C(sp2 )-P bond-forming transformations in water microdroplets at room temperature and atmospheric pressure using N2 as a nebulizing gas. When an aqueous solution of vinylic acid and amine is electrosprayed (+3 kV), the corresponding C(sp2 )-N product is formed in a single step, which was characterized using mass spectrometry (MS) and tandem mass spectrometry (MS2 ). The scope of this reaction was extended to other amines and other unsaturated acids, including acrylic (CH2 =CHCOOH) and crotonic (CH3 CH=CHCOOH) acids. We also found that thiols and phosphines are viable nucleophiles, and the corresponding C(sp2 )-S and C(sp2 )-P products are observed in positive ion mode using MS and MS2 .
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Affiliation(s)
- Yifan Meng
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Elumalai Gnanamani
- Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee, 247667, India
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Adhikari P, Hazarika N, Bhattacharyya K, Das A. Chromium-Catalyzed Cross-Coupling of Methyl Ketones with Cyclic Ketones toward the Selective Synthesis of β-Branched β,γ-Unsaturated Ketones. Org Lett 2024; 26:286-291. [PMID: 38165838 DOI: 10.1021/acs.orglett.3c03960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
Chromium-catalyzed cross-coupling of methyl ketones with cyclic ketones to β-branched β,γ-unsaturated ketones are reported. Interestingly, single-crossed aldol condensation products are formed, even in reactions in which a mixture of products is possible. The reaction is highly chemoselective and regioselective. This catalytic route gives a unique opportunity to integrate the chemistry of the synthetic challenge cross-coupling reaction of ketones and the alkene migration reaction into a reaction pot.
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Affiliation(s)
- Priyanka Adhikari
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India
| | - Nitumoni Hazarika
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India
| | | | - Animesh Das
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India
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9
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Singh T, Atreya V, Jalwal S, Anand A, Chakraborty S. Advances in Group VI Metal-Catalyzed Homogeneous Hydrogenation and Dehydrogenation Reactions. Chem Asian J 2023; 18:e202300758. [PMID: 37815164 DOI: 10.1002/asia.202300758] [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: 08/29/2023] [Revised: 10/10/2023] [Accepted: 10/10/2023] [Indexed: 10/11/2023]
Abstract
Transition metal-catalyzed homogeneous hydrogenation and dehydrogenation reactions for attaining plethora of organic scaffolds have evolved as a key domain of research in academia and industry. These protocols are atom-economic, greener, in line with the goal of sustainability, eventually pave the way for numerous novel environmentally benign methodologies. Appealing progress has been achieved in the realm of homogeneous catalysis utilizing noble metals. Owing to their high cost, less abundance along with toxicity issues led the scientific community to search for sustainable alternatives. In this context, earth- abundant base metals have gained substantial attention culminating enormous progress in recent years, predominantly with pincer-type complexes of nickel, cobalt, iron, and manganese. In this regard, group VI chromium, molybdenum and tungsten complexes have been overlooked and remain underdeveloped despite their earth-abundance and bio-compatibility. This review delineates a comprehensive overview in the arena of homogeneously catalysed (de)hydrogenation reactions using group VI base metals chromium, molybdenum, and tungsten till date. Various reactions have been described; hydrogenation, transfer hydrogenation, dehydrogenation, acceptorless dehydrogenative coupling, hydrogen auto transfer, along with their scope and brief mechanistic insights.
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Affiliation(s)
- Tushar Singh
- Department of Chemistry, Indian Institute of Technology Jodhpur, Karwar, Jodhpur, 342037, Rajasthan
| | - Vaishnavi Atreya
- Department of Chemistry, Indian Institute of Technology Jodhpur, Karwar, Jodhpur, 342037, Rajasthan
| | - Sachin Jalwal
- Department of Chemistry, Indian Institute of Technology Jodhpur, Karwar, Jodhpur, 342037, Rajasthan
| | - Aman Anand
- Department of Chemistry, Indian Institute of Technology Jodhpur, Karwar, Jodhpur, 342037, Rajasthan
| | - Subrata Chakraborty
- Department of Chemistry, Indian Institute of Technology Jodhpur, Karwar, Jodhpur, 342037, Rajasthan
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