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Rani S, Dash SR, Bera A, Alam MN, Vanka K, Maity P. Phosphite mediated asymmetric N to C migration for the synthesis of chiral heterocycles from primary amines. Chem Sci 2021; 12:8996-9003. [PMID: 34276927 PMCID: PMC8261767 DOI: 10.1039/d1sc01217g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/27/2021] [Indexed: 11/21/2022] Open
Abstract
A phosphite mediated stereoretentive C-H alkylation of N-alkylpyridinium salts derived from chiral primary amines was achieved. The reaction proceeds through the activation of the N-alkylpyridinium salt substrate with a nucleophilic phosphite catalyst, followed by a base mediated [1,2] aza-Wittig rearrangement and subsequent catalyst dissociation for an overall N to C-2 alkyl migration. The scope and degree of stereoretention were studied, and both experimental and theoretical investigations were performed to support an unprecedented aza-Wittig rearrangement-rearomatization sequence. A catalytic enantioselective version starting with racemic starting material and chiral phosphite catalyst was also established following our understanding of the stereoretentive process. This method provides efficient access to tertiary and quaternary stereogenic centers in pyridine systems, which are prevalent in drugs, bioactive natural products, chiral ligands, and catalysts.
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Affiliation(s)
- Soniya Rani
- Organic Chemistry Division, CSIR-National Chemical Laboratory Pune-411008 India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad-201002 India
| | - Soumya Ranjan Dash
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad-201002 India
- Physical and Material Chemistry Division, CSIR-National Chemical Laboratory Pune 411008 India
| | - Asish Bera
- Organic Chemistry Division, CSIR-National Chemical Laboratory Pune-411008 India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad-201002 India
| | - Md Nirshad Alam
- Organic Chemistry Division, CSIR-National Chemical Laboratory Pune-411008 India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad-201002 India
| | - Kumar Vanka
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad-201002 India
- Physical and Material Chemistry Division, CSIR-National Chemical Laboratory Pune 411008 India
| | - Pradip Maity
- Organic Chemistry Division, CSIR-National Chemical Laboratory Pune-411008 India
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Nath SR, Joshi KA. Mechanistic investigation in the [1,4] and [1,2] Wittig rearrangement reactions: a DFT study. Phys Chem Chem Phys 2018; 20:21457-21473. [PMID: 30087956 DOI: 10.1039/c8cp01045e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mechanistic pathways for the [1,4] and [1,2] Wittig rearrangements of 2-silyl-6-aryl-5,6-dihydro-(2H)-pyrans have been studied at the M06-2X/6-31+G(d,p), 6-311++G(d,p) and cc-pVTZ level of theory. The crucial C-O bond cleavage step in the mechanism has been analysed initially, using two model reactions covering aliphatic as well as cyclic allylic ethers. The barriers for the one-step as well as two-step pathways have been calculated and the mechanisms for both the [1,4] and [1,2] Wittig rearrangement reactions are predicted to occur through a two-step mode. An energetic analysis of the reaction pathways reveals that the [1,4]-rearrangement has a lower barrier than the [1,2]-Wittig rearrangement. The C-O cleavage transition state was found to have the highest barrier and is thus the rate determining transition state for all of the studied molecules. This is in agreement with the previously published experimental studies. The role of the allylic trimethylsilane group in the stabilization of the intermediate anions of the Wittig reactants has also been investigated while comparing it with the phenyl and allylic t-butyl groups through Natural Bond Orbital (NBO) calculations.
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Affiliation(s)
- Shilpa R Nath
- Department of Chemistry, Institute of Chemical Technology, Matunga, Mumbai 400019, India.
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4
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Ho GM, Li YJ. Tandem [1,2]-Wittig Rearrangement/Lactonization of γ-Benzyloxy Vinylogous Urethanes: Application to the Synthetic Studies of Maculalactone A, Planchol C and γ-Lycorane. ASIAN J ORG CHEM 2017. [DOI: 10.1002/ajoc.201700589] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Guo-Ming Ho
- Department of Applied Chemistry; National Chiayi University; 300 Syuefu Road Chiayi City 60004 Taiwan
- Genomics Research Center; Academia Sinica; 128 Academia Road, Section 2 Taipei 11529 Taiwan
| | - Yu-Jang Li
- Department of Applied Chemistry; National Chiayi University; 300 Syuefu Road Chiayi City 60004 Taiwan
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Barry JT, Berg DJ, Tyler DR. Radical Cage Effects: The Prediction of Radical Cage Pair Recombination Efficiencies Using Microviscosity Across a Range of Solvent Types. J Am Chem Soc 2017; 139:14399-14405. [PMID: 28931277 DOI: 10.1021/jacs.7b04499] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study reports a method for correlating the radical recombination efficiencies (FcP) of geminate radical cage pairs to the properties of the solvent. Although bulk viscosity (macroviscosity) is typically used to predict or interpret radical recombination efficiencies, the work reported here shows that microviscosity is a much better parameter. The use of microviscosity is valid over a range of different solvent system types, including nonpolar, aromatic, polar, and hydrogen bonding solvents. In addition, the relationship of FcP to microviscosity holds for solvent systems containing mixtures of these solvent types. The microviscosities of the solvent systems were straightforwardly determined by measuring the diffusion coefficient of an appropriate probe by NMR DOSY spectroscopy. By using solvent mixtures, selective solvation was shown to not affect the correlation between FcP and microviscosity. In addition, neither solvent polarity nor radical rotation affects the correlation between FcP and the microviscosity.
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Affiliation(s)
- Justin T Barry
- Department of Chemistry and Biochemistry, University of Oregon , 1253 University of Oregon, Eugene, Oregon 97403, United States
| | - Daniel J Berg
- Department of Chemistry and Biochemistry, University of Oregon , 1253 University of Oregon, Eugene, Oregon 97403, United States
| | - David R Tyler
- Department of Chemistry and Biochemistry, University of Oregon , 1253 University of Oregon, Eugene, Oregon 97403, United States
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Barry JT, Berg DJ, Tyler DR. Radical Cage Effects: Comparison of Solvent Bulk Viscosity and Microviscosity in Predicting the Recombination Efficiencies of Radical Cage Pairs. J Am Chem Soc 2016; 138:9389-92. [DOI: 10.1021/jacs.6b05432] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Justin T. Barry
- Department
of Chemistry and Biochemistry, University of Oregon, 1253 University
of Oregon, Eugene, Oregon 97403, United States
| | - Daniel J. Berg
- Department
of Chemistry and Biochemistry, University of Oregon, 1253 University
of Oregon, Eugene, Oregon 97403, United States
| | - David R. Tyler
- Department
of Chemistry and Biochemistry, University of Oregon, 1253 University
of Oregon, Eugene, Oregon 97403, United States
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Gao F, Kim BS, Walsh PJ. Chemoselective Palladium-Catalyzed Deprotonative Arylation/[1,2]-Wittig Rearrangement of Pyridylmethyl Ethers. Chem Sci 2016; 7:976-983. [PMID: 27014434 PMCID: PMC4800319 DOI: 10.1039/c5sc02739j] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 10/26/2015] [Indexed: 12/16/2022] Open
Abstract
Control of chemoselectivity is one of the most challenging problems facing chemists and is particularly important in the synthesis of bioactive compounds and medications. Herein, the first highly chemoselective tandem C(sp3)-H arylation/[1,2]-Wittig rearrangement of pyridylmethyl ethers is presented. The efficient and operationally simple protocols enable generation of either arylation products or tandem arylation/[1,2]-Wittig rearrangement products with remarkable selectivity and good to excellent yields (60-99%). Choice of base, solvent, and reaction temperature play a pivotal role in tuning the reactivity of intermediates and controlling the relative rates of competing processes. The novel arylation step is catalyzed by a Pd(OAc)2/NIXANTPHOS-based system via a deprotonative cross-coupling process. The method provides rapid access to skeletally diverse aryl(pyridyl)methanol core structures, which are central components of several medications.
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Affiliation(s)
- Feng Gao
- Department of Medicinal Plants , Agronomy College , Sichuan Agricultural University , 211, Huimin Rd, Wenjiang Region , Chengdu 611130 , PR China
- Roy and Diana Vagelos Laboratories , Penn/Merck Laboratory for High-Throughput Experimentation , Department of Chemistry , University of Pennsylvania , 231 S, 34th St. , Philadelphia , PA 19104-6323 , USA . ; https://sites.google.com/site/titaniumupenn/ ; Fax: +1-215-573-6743
| | - Byeong-Seon Kim
- Roy and Diana Vagelos Laboratories , Penn/Merck Laboratory for High-Throughput Experimentation , Department of Chemistry , University of Pennsylvania , 231 S, 34th St. , Philadelphia , PA 19104-6323 , USA . ; https://sites.google.com/site/titaniumupenn/ ; Fax: +1-215-573-6743
| | - Patrick J. Walsh
- Roy and Diana Vagelos Laboratories , Penn/Merck Laboratory for High-Throughput Experimentation , Department of Chemistry , University of Pennsylvania , 231 S, 34th St. , Philadelphia , PA 19104-6323 , USA . ; https://sites.google.com/site/titaniumupenn/ ; Fax: +1-215-573-6743
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Gao PS, Ye F, Dong XY, Chen Y, Gao ZW, Zhang WQ, Xu LW. Base-promoted [1,4]-Wittig rearrangement of chalcone-derived allylic ethers leading to aromatic β-benzyl ketones. RSC Adv 2015. [DOI: 10.1039/c5ra03846d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Strong base promoted [1,4]-Wittig rearrangement of allylic ethers was developed in this work, in which the reaction provided a facile approach to the synthesis of aromatic β-benzyl ketones under controllable radical reaction conditions.
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Affiliation(s)
- Pei-Sen Gao
- Key Laboratory of Applied Surface and Colloid Chemistry
- Ministry of Education (MOE)
- School of Chemistry and Chemical Engineering
- Shaanxi Normal University
- Xi'an 710062
| | - Fei Ye
- Key Laboratory of Organosilicon Chemistry
- Material Technology of Ministry of Education
- Hangzhou Normal University
- Hangzhou 310012
- P. R. China
| | - Xiao-Yun Dong
- Key Laboratory of Applied Surface and Colloid Chemistry
- Ministry of Education (MOE)
- School of Chemistry and Chemical Engineering
- Shaanxi Normal University
- Xi'an 710062
| | - Yun Chen
- Key Laboratory of Applied Surface and Colloid Chemistry
- Ministry of Education (MOE)
- School of Chemistry and Chemical Engineering
- Shaanxi Normal University
- Xi'an 710062
| | - Zi-Wei Gao
- Key Laboratory of Applied Surface and Colloid Chemistry
- Ministry of Education (MOE)
- School of Chemistry and Chemical Engineering
- Shaanxi Normal University
- Xi'an 710062
| | - Wei-Qiang Zhang
- Key Laboratory of Applied Surface and Colloid Chemistry
- Ministry of Education (MOE)
- School of Chemistry and Chemical Engineering
- Shaanxi Normal University
- Xi'an 710062
| | - Li-Wen Xu
- Key Laboratory of Applied Surface and Colloid Chemistry
- Ministry of Education (MOE)
- School of Chemistry and Chemical Engineering
- Shaanxi Normal University
- Xi'an 710062
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9
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Wang CY, Dong C, Zheng ZJ, Xu Z, Yang KF, Xu LW. Construction of an all-substituted pyrrolidine derivative with multiple stereogenic centers and Betti-base-derived γ-amino alcohols by [1,2]-Wittig rearrangement. RSC Adv 2015. [DOI: 10.1039/c5ra09145d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The construction of Betti base-derived γ-amino alcohols and all-substituted pyrrolidine derivative with multiple stereogenic centers has been developed successfully through neighboring lithium-assisted [1,2]-Wittig rearrangement (NLAWR).
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Affiliation(s)
- Cai-Yun Wang
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Cheng Dong
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Zhan-Jiang Zheng
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Zheng Xu
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Ke-Fang Yang
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Li-Wen Xu
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
- State Key Laboratory for Oxo Synthesis and Selective Oxidation
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Zheng LS, Jiang KZ, Deng Y, Bai XF, Gao G, Gu FL, Xu LW. Synthesis of Ar-BINMOL Ligands by [1,2]-Wittig Rearrangement to Probe Their Catalytic Activity in 1,2-Addition Reactions of Aldehydes with Grignard Reagents. European J Org Chem 2012. [DOI: 10.1002/ejoc.201201301] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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11
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Montaña ÁM, Ponzano S, Batalla C, Font-Bardia M. Unprecedented double benzylic rearrangement: regio- and stereospecific tandem 1,4-shift and Curtin rearrangement. Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.07.053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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12
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Brekan JA, Chernyak D, White KL, Scheidt KA. Lewis base-promoted carbon–carbon sp3–sp3 coupling reactions of α-silyl silylethers. Chem Sci 2012. [DOI: 10.1039/c2sc00581f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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13
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Gao G, Gu FL, Jiang JX, Jiang K, Sheng CQ, Lai GQ, Xu LW. Neighboring Lithium-Assisted [1,2]-Wittig Rearrangement: Practical Access to Diarylmethanol-Based 1,4-Diols and Optically Active BINOL Derivatives with Axial and sp3-Central Chirality. Chemistry 2011; 17:2698-703. [DOI: 10.1002/chem.201003111] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Indexed: 11/08/2022]
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He A, Falck JR. Synthesis of enantioenriched alpha-(hydroxyalkyl)-tri-n-butylstannanes. Angew Chem Int Ed Engl 2008; 47:6586-9. [PMID: 18646026 DOI: 10.1002/anie.200802313] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Anyu He
- Department of Biochemistry, University of Texas, Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038, USA
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He A, Falck J. Synthesis of Enantioenriched α-(Hydroxyalkyl)-tri-n-butylstannanes. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200802313] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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16
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Harris JD, Oelkers AB, Tyler DR. The Solvent Cage Effect: Is There a Spin Barrier to Recombination of Transition Metal Radicals? J Am Chem Soc 2007; 129:6255-62. [PMID: 17447764 DOI: 10.1021/ja069295s] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
This investigation explored whether there is a spin barrier to recombination of first- and second-row transition metal-centered radicals in a radical cage pair. To answer this question, the recombination efficiencies of photochemically generated radical cage pairs (denoted as FcP) were measured in the presence and absence of an external heavy atom probe. Two methods were employed for measuring the cage effect. The first method was femtosecond pump-probe transient absorption spectroscopy, which directly measured FcP from reaction kinetics, and the second method (referred to herein as the "steady-state" method) obtained FcP from quantum yields for the radical trapping reaction with CCl4 as a function of solvent viscosity. Both methods generated radical cage pairs by photolysis (lambda = 515 nm for the pump probe method and lambda = 546 nm for the steady-state method) of Cp'2Mo2(CO)6 (Cp' = eta(5)-C5H4CH3). In addition, radical cage pairs generated from Cp'2Fe2(CO)4 and Cp*2TiCl2 (Cp* = eta(5)-C5(CH3)5) were studied by the steady-state method. The pump-probe method used p-dichlorobenzene as the heavy atom perturber, whereas the steady-state method used iodobenzene. For both methods and for all the radical caged pairs investigated, there were no observable heavy atom effects, from which it is concluded there is no spin barrier to recombination.
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Affiliation(s)
- John D Harris
- Department of Chemistry, University of Oregon, Eugene, Oregon 97403, USA
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17
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Onyeozili EN, Maleczka RE. alpha-Substituted acylsilanes via a highly selective [1,4]-Wittig rearrangement of alpha-benzyloxyallylsilane. Chem Commun (Camb) 2006:2466-8. [PMID: 16758017 DOI: 10.1039/b603228a] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
alpha-Benzyloxyallylsilane undergoes efficient [1,4]-Wittig rearrangement to generate an enolate intermediate that can be trapped with various electrophiles, thereby providing a new synthetic approach to substituted acylsilanes.
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Affiliation(s)
- Edith N Onyeozili
- Department of Chemistry, Michigan State University, 540 Chemistry, East Lansing, Michigan 48824, USA
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18
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Lemiègre L, Regnier T, Combret JC, Maddaluno J. Conjugated elimination versus [1,2]-Wittig rearrangement of unsaturated diox(ol)anes. Tetrahedron Lett 2003. [DOI: 10.1016/s0040-4039(02)02568-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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19
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Zhang Y, Reynolds NT, Manju K, Rovis T. Stereoretentive O-to-C rearrangement of vinyl acetals: solvent cage effects as a stereocontrol element. J Am Chem Soc 2002; 124:9720-1. [PMID: 12175226 DOI: 10.1021/ja026972j] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Lewis acid-mediated rearrangement of chiral vinyl acetals may be induced to provide the product of stereoretention using Me3Al and BF3.OEt2 in concert. The selectivities obtained in this reaction (86:14 to 96:4) are complementary to that observed when relying on oxocarbenium facial bias to control the newly formed stereocenter. Evidence is presented that this reaction occurs by tight ion-pair binding in the solvent cage. The relay of C-O bond stereochemistry to a C-C bond stereocenter via ionic intermediates is an addition to similar established methods such as the Claisen rearrangement.
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Affiliation(s)
- Yongda Zhang
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA
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Capriati V, Florio S, Ingrosso G, Granito C, Troisi L. Stereoselective and Competitive [1,2]‐ and [2,3]‐Wittig Rearrangements of Allyl Heteroarylalkyl Ethers. European J Org Chem 2002. [DOI: 10.1002/1099-0690(20022)2002:3<478::aid-ejoc478>3.0.co;2-#] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Vito Capriati
- Centro CNR “M.I.S.O.”, Dipartimento Farmaco‐Chimico, University of Bari, Via E. Orabona 4, 70125 Bari, Italy
| | - Saverio Florio
- Centro CNR “M.I.S.O.”, Dipartimento Farmaco‐Chimico, University of Bari, Via E. Orabona 4, 70125 Bari, Italy
| | - Giovanni Ingrosso
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, University of Lecce, Via Prov. le Lecce‐Monteroni, 73100 Lecce, Italy, Fax: (internat.) + 39‐0832/320‐701
| | - Catia Granito
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, University of Lecce, Via Prov. le Lecce‐Monteroni, 73100 Lecce, Italy, Fax: (internat.) + 39‐0832/320‐701
| | - Luigino Troisi
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, University of Lecce, Via Prov. le Lecce‐Monteroni, 73100 Lecce, Italy, Fax: (internat.) + 39‐0832/320‐701
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Abad A, Agulló C, Cuñat AC, Jiménez D, Perni RH. New route to herbertanes via a Suzuki cross-coupling reaction: synthesis of herbertenediol. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(01)00987-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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22
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Kitagawa O, Momose SI, Yamada Y, Shiro M, Taguchi T. Synthesis of optically active aldol derivatives through chirality transfer type 1,2-Wittig rearrangement of α-alkoxycarboxamides. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(01)00868-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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23
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Hart SA, Trindle CO, Etzkorn FA. Solvent-dependent stereoselectivity in a Still-Wittig rearrangement: an experimental and ab initio study. Org Lett 2001; 3:1789-91. [PMID: 11405712 DOI: 10.1021/ol015764d] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
[see reaction]. The Still-Wittig rearrangement gave opposite selectivities for (Z:E)-alkenes in THF (3:1) vs toluene (1:3) in the synthesis of serine-proline dipeptide amide isosteres. Four transition states leading to (Z)-and (E)-alkenes with THF and without (representing toluene) were identified by ab initio calculations at the 3-21G* level. The calculated (Z:E)-ratios with THF (4.7:1) and without THF (1:3.2) suggested that the transition state geometries and energies were well-represented by the calculations.
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Affiliation(s)
- S A Hart
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, USA
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R. Katritzky A, Fang Y. Benzotriazole-mediated [1,2]-Wittig Rearrangement. The Preparation of Homoalcohols from Ethers. HETEROCYCLES 2000. [DOI: 10.3987/com-00-8945] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Abstract
[formula: see text] The Wittig rearrangements of alpha-alkoxysilanes, promoted by the action of methyllithium were studied. Depending on both the substrate and reaction conditions employed, [2,3]-, [1,2]-, or [1,4]-Wittig rearrangements can be realized. These rearrangements were shown to be initiated by either Si/Li exchange or deprotonation alpha to the silane. Furthermore the sigmatropic shifts can often be followed by other synthetically useful in situ chemical events.
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Affiliation(s)
- R E Maleczka
- Department of Chemistry, Michigan State University, East Lansing 48824, USA.
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Maleczka RE, Geng F. Synthesis and fluoride-promoted wittig rearrangements of alpha-alkoxysilanes. Org Lett 1999; 1:1111-3. [PMID: 10825963 DOI: 10.1021/ol9909132] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[formula: see text] Lewis acid-catalyzed reaction of allyl and benzyl trichloroacetimidates with alpha-silyl alcohols was found to be a general method for the synthesis of alpha-alkoxysilanes. Upon exposure to CsF, these alpha-alkoxysilanes could be made to undergo [2,3]-Wittig rearrangement with an efficiency similar to that realized by the analogous but inherently more toxic alpha-alkoxystannanes.
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Affiliation(s)
- R E Maleczka
- Department of Chemistry, Michigan State University, East Lansing 48824, USA.
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