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Islam B, Colby DA. Transient Formation of Hemiketals from Pentafluoro- gem-diols in the Presence of Alcohols. J Fluor Chem 2023; 270:110162. [PMID: 37546180 PMCID: PMC10399912 DOI: 10.1016/j.jfluchem.2023.110162] [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] [Indexed: 08/08/2023]
Abstract
Pentafluoro-gem-diols have emerged as a source of reactive intermediates for synthesizing fluorinated molecules. When pentafluoro-gem-diols were exposed to alcohols as solvents, the formation of transient hemiketals was detected by 19F NMR. The conversion rates to hemiketals were found to be higher with primary alcohols than with secondary or fluorinated alcohols. These findings provide valuable insight for developing novel techniques to construct intricate fluorinated structures using pentafluoro-gem-diols.
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Affiliation(s)
- Baharul Islam
- Department of BioMolecular Sciences, University of Mississippi, University, Mississippi, U.S.A
| | - David A Colby
- Department of BioMolecular Sciences, University of Mississippi, University, Mississippi, U.S.A
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2
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Motiwala HF, Armaly AM, Cacioppo JG, Coombs TC, Koehn KRK, Norwood VM, Aubé J. HFIP in Organic Synthesis. Chem Rev 2022; 122:12544-12747. [PMID: 35848353 DOI: 10.1021/acs.chemrev.1c00749] [Citation(s) in RCA: 117] [Impact Index Per Article: 58.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
1,1,1,3,3,3-Hexafluoroisopropanol (HFIP) is a polar, strongly hydrogen bond-donating solvent that has found numerous uses in organic synthesis due to its ability to stabilize ionic species, transfer protons, and engage in a range of other intermolecular interactions. The use of this solvent has exponentially increased in the past decade and has become a solvent of choice in some areas, such as C-H functionalization chemistry. In this review, following a brief history of HFIP in organic synthesis and an overview of its physical properties, literature examples of organic reactions using HFIP as a solvent or an additive are presented, emphasizing the effect of solvent of each reaction.
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Affiliation(s)
- Hashim F Motiwala
- Divison of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States
| | - Ahlam M Armaly
- Divison of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States
| | - Jackson G Cacioppo
- Divison of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States
| | - Thomas C Coombs
- Department of Chemistry, University of North Carolina Wilmington, Wilmington, North Carolina 28403 United States
| | - Kimberly R K Koehn
- Divison of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States
| | - Verrill M Norwood
- Divison of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States
| | - Jeffrey Aubé
- Divison of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States
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3
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Sowaileh MF, Alshammari MD, Colby DA. Synthesis of Difluorinated Halohydrins by the Chemoselective Addition of Difluoroenolates to α-Haloketones. Org Lett 2021; 23:5098-5101. [PMID: 34124917 DOI: 10.1021/acs.orglett.1c01636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
α-Haloketones are valuable intermediates in the synthesis of pharmaceuticals and natural products because they display two electrophiles. Although chemoselective additions to each of these functional groups are known, the use of fluorinated nucleophiles has not been characterized, except for the dimerization of fluorohalomethyl ketones. Our studies demonstrate the use of difluoroenolates to create difluorinated bromohydrins and chlorohydrins from α-haloketones without any cyclization or rearrangement due to the mild conditions.
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Affiliation(s)
- Munia F Sowaileh
- Department of BioMolecular Sciences, University of Mississippi, University, Mississippi 38677, United States
| | - Maali D Alshammari
- Department of BioMolecular Sciences, University of Mississippi, University, Mississippi 38677, United States
| | - David A Colby
- Department of BioMolecular Sciences, University of Mississippi, University, Mississippi 38677, United States
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4
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Zhu X, Huang Y, Xu X, Qing F. Iron-catalyzed cyanoalkylation of difluoroenol silyl ethers with cyclobutanone oxime esters. CHINESE CHEM LETT 2021. [DOI: 10.1016/j.cclet.2021.07.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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5
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Su HY, Zhu XL, Huang Y, Xu XH, Qing FL. Copper-catalyzed chemoselective C-H functionalization of quinoxalin-2(1 H)-ones with hexafluoroisopropanol. Chem Commun (Camb) 2020; 56:12805-12808. [PMID: 32966399 DOI: 10.1039/d0cc05623e] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
An unexpected three-component reaction of quinoxalin-2(1H)-ones, tert-butyl peroxybenzoate (TBPB), and hexafluoroisopropanol (HFIP) is described. Under CuBr-catalyzed and TBPB-oxidized conditions, a variety of hydroxyhexafluoroisobutylated quinoxalin-2(1H)-ones were formed. Furthermore, the first hexafluoroisopropoxylation of the quinoxalin-2(1H)-ones with HFIP is also demonstrated with Cu2O as the catalyst and PhI(OAc)2 as the oxidant. These new transformations of HFIP furnish previously unknown and potentially useful fluorinated quinoxalin-2(1H)-one derivatives.
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Affiliation(s)
- Hai-Yan Su
- College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Lu, Shanghai 201620, China.
| | - Xiao-Lei Zhu
- College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Lu, Shanghai 201620, China.
| | - Yangen Huang
- College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Lu, Shanghai 201620, China.
| | - Xiu-Hua Xu
- Key Laboratory of Organofluorine Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Science, Chinese Academy of Science, 345 Lingling Lu, Shanghai 200032, China.
| | - Feng-Ling Qing
- College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Lu, Shanghai 201620, China. and Key Laboratory of Organofluorine Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Science, Chinese Academy of Science, 345 Lingling Lu, Shanghai 200032, China.
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6
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Qu CH, Song GT, Tang DY, Shao JW, Li HY, Xu ZG, Chen ZZ. Microwave-Assisted Copper Catalysis of α-Difluorinated gem-Diol toward Difluoroalkyl Radical for Hydrodifluoroalkylation of para-Quinone Methides. J Org Chem 2020; 85:12785-12796. [PMID: 32847359 DOI: 10.1021/acs.joc.0c01686] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reported herein is a unified strategy to generate difluoroalkyl radicals from readily prepared α-difluorinated gem-diols by single electron oxidation. Under microwave irradiation, a catalytic amount of oxidant Cu(OAc)2 succeeds in the formation of transient difluoroalkyl radicals in situ, for the first time. The reaction features a simple protocol, short reaction time, scalability, and high yield. The synthetic utility of this new methodology was also explored for the synthesis of difluoroalkylated spiro-cyclohexadienones, which is an important core structure in natural products and pharmaceuticals.
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Affiliation(s)
- Chuan-Hua Qu
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Gui-Ting Song
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing University of Arts and Sciences, Chongqing 402160, China.,Institute of Bioorganic & Medicinal Chemistry, Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
| | - Dian-Yong Tang
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Jing-Wei Shao
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, United States
| | - Hong-Yu Li
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, United States
| | - Zhi-Gang Xu
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Zhong-Zhu Chen
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing University of Arts and Sciences, Chongqing 402160, China
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Khatri HR, Han C, Luong E, Pan X, Adam AT, Alshammari MD, Shao Y, Colby DA. Controlling the Cleavage of Carbon-Carbon Bonds To Generate α,α-Difluorobenzyl Carbanions for the Construction of Difluoromethylbenzenes. J Org Chem 2019; 84:11665-11675. [PMID: 31449418 PMCID: PMC8262649 DOI: 10.1021/acs.joc.9b01595] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Controlling the cleavage of carbon-carbon bonds during a chemical reaction is a substantial challenge; however, synthetic methods that accomplish this objective produce valuable and often unexplored reactivity. We have designed a mild process to generate α,α-difluorobenzyl carbanions in the presence of potassium carbonate by exploiting the cleavage of C-C bonds during the release of trifluoroacetate. The initiating reagent is potassium carbonate, which represents an improvement over existing protocols that require a strong base. Fragmentation studies across substituted arenes and heteroarenes were conducted along with computational analyses to elucidate reactivity trends. Furthermore, the mildly generated α,α-difluorobenzyl carbanions from electron-deficient aromatics and heteroaromatic rings can react with aldehydes to create derivatives of difluoromethylbenzenes, which are valuable synthetic targets.
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Affiliation(s)
- Hari R. Khatri
- Department of BioMolecular Sciences, University of Mississippi, University, Mississippi 38677, United States
| | - Changho Han
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, United States
| | - Erica Luong
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Xiaoliang Pan
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Amna T. Adam
- Department of BioMolecular Sciences, University of Mississippi, University, Mississippi 38677, United States
| | - Maali D. Alshammari
- Department of BioMolecular Sciences, University of Mississippi, University, Mississippi 38677, United States
| | - Yihan Shao
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - David A. Colby
- Department of BioMolecular Sciences, University of Mississippi, University, Mississippi 38677, United States
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8
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Mei H, Liu J, Fustero S, Román R, Ruzziconi R, Soloshonok VA, Han J. Chemistry of detrifluoroacetylativelyin situgenerated fluoro-enolates. Org Biomol Chem 2019; 17:762-775. [DOI: 10.1039/c8ob02843e] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review article provides a summary of the detrifluoroacetylativein situgeneration of fluorine-containing enolates and their related reactions.
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Affiliation(s)
- Haibo Mei
- College of Chemical Engineering
- Nanjing Forestry University
- Nanjing
- China
| | - Jiang Liu
- College of Chemical Engineering
- Nanjing Forestry University
- Nanjing
- China
| | - Santos Fustero
- Departamento de Química Orgánica
- Universidad de Valencia
- 46100 Burjassot
- Spain
- Laboratorio de Moléculas Orgánicas
| | - Raquel Román
- Departamento de Química Orgánica
- Universidad de Valencia
- 46100 Burjassot
- Spain
- Laboratorio de Moléculas Orgánicas
| | - Renzo Ruzziconi
- Department of Chemistry
- Biology and Biotechnologies
- 06123 Perugia
- Italy
| | - Vadim A. Soloshonok
- Department of Organic Chemistry I
- Faculty of Chemistry
- University of the Basque Country UPV/EHU
- 20018 San Sebastián
- Spain
| | - Jianlin Han
- College of Chemical Engineering
- Nanjing Forestry University
- Nanjing
- China
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Reddy MK, Ramakrishna I, Baidya M. Divergent Reactivity of gem-Difluoro-enolates toward Nitrogen Electrophiles: Unorthodox Nitroso Aldol Reaction for Rapid Synthesis of α-Ketoamides. Org Lett 2018; 20:4610-4613. [PMID: 30033729 DOI: 10.1021/acs.orglett.8b01900] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
An amination reaction of in situ generated gem-difluoro-enolates has been explored with electrophilic nitrogen sources. While their exposure to azodicarboxylates smoothly produced fluorinated α-amino ketones, reaction with nitrosoarenes (nitroso aldol reaction) furnished α-ketoamides in very high yields (up to 94%). The reaction is very fast (typically completed within 5 min) and scalable and tolerates various sensitive functional groups. Synthetic utility of this process was highlighted through the production of diverse nitrogen heterocycles and an orexin receptor antagonist.
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Affiliation(s)
- Mallu Kesava Reddy
- Department of Chemistry , Indian Institute of Technology Madras , Chennai 600 036 , Tamil Nadu , India
| | - Isai Ramakrishna
- Department of Chemistry , Indian Institute of Technology Madras , Chennai 600 036 , Tamil Nadu , India
| | - Mahiuddin Baidya
- Department of Chemistry , Indian Institute of Technology Madras , Chennai 600 036 , Tamil Nadu , India
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10
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Nguyen AL, Khatri HR, Woods JR, Baldwin CS, Fronczek FR, Colby DA. Magnesium-Promoted Additions of Difluoroenolates to Unactivated Imines. J Org Chem 2018; 83:3109-3118. [PMID: 29446944 DOI: 10.1021/acs.joc.7b03014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Although there are many synthetic methods to produce fluorinated and trifluoromethylated organic structures, the construction of difluoromethylated compounds remains a synthetic challenge. We have discovered that unactivated imines will react with difluoroenolates under exceedingly mild conditions when using magnesium salts and organic bases. We have applied this approach to the iminoaldol reaction to produce difluoromethylene groups as α,α-difluoro-β-amino-carbonyl groups. This method provides synthetically useful quantities of difficult to access α,α-difluoro-β-aminoketones without the need of protecting groups or the use of activated imines. Moreover, we have applied this strategy to create analogues of the dual orexin receptor antagonist, almorexant, in only two synthetic steps.
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Affiliation(s)
- Alex L Nguyen
- Department of BioMolecular Sciences , University of Mississippi , University , Mississippi 38677 , United States
| | - Hari R Khatri
- Department of BioMolecular Sciences , University of Mississippi , University , Mississippi 38677 , United States
| | - James R Woods
- Department of Medicinal Chemistry and Molecular Pharmacology , Purdue University , West Lafayette , Indiana 47907 , United States
| | - Cassidy S Baldwin
- Department of BioMolecular Sciences , University of Mississippi , University , Mississippi 38677 , United States
| | - Frank R Fronczek
- Department of Chemistry , Louisiana State University , Baton Rouge , Louisiana 70803 , United States
| | - David A Colby
- Department of BioMolecular Sciences , University of Mississippi , University , Mississippi 38677 , United States
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11
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Peng P, Wu JJ, Liang JQ, Zhang TY, Huang JW, Wu FH. Lithium triethylborohydride-promoted generation of α,α-difluoroenolates from 2-iodo-2,2-difluoroacetophenones: an unprecedented utilization of lithium triethylborohydride. RSC Adv 2017. [DOI: 10.1039/c7ra12130j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Lithium triethylborohydride was found to promote the generation of α,α-difluoroenolates from 2-iodo-2,2-difluoroacetophenones, and applied to the synthesis of polyfluorinated β-hydroxy ketones via self-condensation or aldol reaction.
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Affiliation(s)
- Peng Peng
- School of Chemical and Environmental Engineering
- Shanghai Institute of Technology
- Shanghai 201418
- China
| | - Jing-jing Wu
- School of Chemical and Environmental Engineering
- Shanghai Institute of Technology
- Shanghai 201418
- China
- Key Laboratory of Organofluorine Chemistry
| | - Jun-qing Liang
- School of Chemical and Environmental Engineering
- Shanghai Institute of Technology
- Shanghai 201418
- China
| | - Tian-yu Zhang
- School of Chemical and Environmental Engineering
- Shanghai Institute of Technology
- Shanghai 201418
- China
| | - Jin-wen Huang
- School of Chemical and Environmental Engineering
- Shanghai Institute of Technology
- Shanghai 201418
- China
- Key Laboratory of Organofluorine Chemistry
| | - Fan-hong Wu
- School of Chemical and Environmental Engineering
- Shanghai Institute of Technology
- Shanghai 201418
- China
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