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Young Hoon Jung - One of the best experts on this subject based on the ideXlab platform.
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total synthesis of codonopsinine via regioselective and diastereoselective amination using Chlorosulfonyl Isocyanate
Tetrahedron, 2017Co-Authors: Young Jae Choi, Sook Jin Park, In Su Kim, Yoo Chang Kim, Jun Min Jung, Yeon Su Kim, Young Hoon JungAbstract:Abstract The total synthesis of (−)-codonopsinine ( 1 ) from the readily available ( S )-3-chloropropan-1,2-diol is described. The key steps for the preparation of (−)-codonopsinine ( 1 ) involve the regioselective and diastereoselective amination of anti -1,2-dibenzyl ether 11 using Chlorosulfonyl Isocyanate and intramolecular amidomercuration to form the pyrrolidine ring. Notably, the reaction between anti -1,2-dibenzyl ether and Chlorosulfonyl Isocyanate in toluene at 0 °C produced the corresponding anti -1,2-amino alcohol 12a as a major product with excellent diastereoselectivity ( anti : syn = 29:1). This observation can be explained by the neighboring group participation leading to the retention of stereochemistry.
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divergent synthesis of aminocyclopentitol analogues via stereoselective amination of cyclic polybenzyl ether with Chlorosulfonyl Isocyanate
Synlett, 2015Co-Authors: Young Hoon Jung, Sook Jin Park, Yeon Ju Hong, Kyungtae Kang, Seung In Kim, So Yeon Kim, Jung Sang Park, In Su KimAbstract:The divergent synthesis of some novel aminocyclopentitol analogues was concisely achieved from readily available d -galactose via the highly diastereoselective amination of carbocyclic polybenzyl ether using Chlorosulfonyl Isocyanate, diastereoselective dihydroxylation, and epoxidation as the key steps.
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total synthesis of carbocyclic nucleoside neplanocin a
Tetrahedron, 2015Co-Authors: Young Hoon Jung, Sook Jin Park, Yeon Ju Hong, Kyungtae KangAbstract:Abstract Asymmetric total synthesis of (+)-neplanocin A was concisely achieved from readily available d -galactose via the regioselective and diastereoselective amination of carbocyclic polybenzyl ether using Chlorosulfonyl Isocyanate and intramolecular olefin metathesis using second-generation Grubbs catalyst.
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total synthesis of valienamine and 1 epi valienamine via a highly diastereoselective allylic amination of cyclic polybenzyl ether using Chlorosulfonyl Isocyanate
Tetrahedron, 2013Co-Authors: Seung In Kim, Sook Jin Park, In Su Kim, Hye Ran Yang, Reum A Baek, Young Hoon JungAbstract:Abstract The total synthesis of (+)-valienamine and (−)-1-epi-valienamine was concisely accomplished from readily available d -glucose via a highly diastereoselective amination of chiral benzylic ether using Chlorosulfonyl Isocyanate, intramolecular olefin metathesis, and diastereoselective reduction of cyclic enone using l -Selectride as the key steps.
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asymmetric formal synthesis of swainsonine by a highly regioselective and diastereoselective allylic amination using Chlorosulfonyl Isocyanate
European Journal of Organic Chemistry, 2013Co-Authors: Guang Ri Dong, Sook Jin Park, In Su Kim, Yong Rae Hong, Young Hoon JungAbstract:A concise asymmetric formal synthesis of (–)-swainsonine from readily available D-erythronolactone is described. The key steps include a highly diastereoselective amination of a chiral benzylic ether, which occurs with the retention of stereochemistry using Chlorosulfonyl Isocyanate, and a palladium-catalyzed decarboxylative N-allylation of an allyl carbamate.
Marek Chmielewski - One of the best experts on this subject based on the ideXlab platform.
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stereochemistry of the 2 2 cycloaddition of Chlorosulfonyl Isocyanate to chiral alkoxyallenes derived from 1 3 alkylidene l erythritol and d threitol
European Journal of Organic Chemistry, 2005Co-Authors: Tong Thanh Danh, Jadwiga Frelek, Lech Kozerski, Wojciech Bocian, Patrycja Szczukiewicz, Marek ChmielewskiAbstract:The [2+2] cycloaddition of Chlorosulfonyl Isocyanate to alkoxyallenes derived from ethylidene and benzylidene erythritols and threitols proceeds with a moderate asymmetric induction in the case of the erythritols and with a very low induction in the case of threitols. This indicates that the erythritol derivatives may exist in solution in one predominant conformation while the threitol derivatives behave as a conformational ensemble. The conformations of alkoxyallenes were studied with variety of NMR techniques as well as using ab initio calculations. The results thus obtained were in a full agreement with our predictions based on the stereoselectivity of cycloaddition. The azetidinones obtained by the cycloaddition were subjected to intramolecular alkylation at the nitrogen atom to provide the corresponding tricyclic cephams. The absolute configurations of the resultant azetidinones and cephams were assigned using NMR and CD spectroscopy. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
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2 2 cycloaddition of Chlorosulfonyl Isocyanate to z propenyl ethers bound to polystyrene resins by alkylsulfonyl linkers
European Journal of Organic Chemistry, 2004Co-Authors: Robert łysek, Bartlomiej Furman, Barbara Grzeszczyk, Marek ChmielewskiAbstract:The 3-O- and 5-O-(Z)-propenyl ethers derived from 1,2-O-isopropylidene-α-D-xylo- and glucofuranoses, respectively, were attached to the Merrifield, MPPC and NCPSC resins using alkylsulfonyl linkers. The [2+2]-cycloaddition of Chlorosulfonyl Isocyanate to the polymer-bound vinyl ethers followed by the intramolecular alkylation of the β-lactam nitrogen led to the formation of mixtures of the corresponding diastereomeric oxacephams or clavams with a low stereoselectivity. In the case of Merrifield and MPP resins, the β-lactams were accompanied by the corresponding oxetanes or oxiranes. Reactions performed using soluble polymer proceeded similarly to those carried out in solution. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
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solid phase 2 2 cycloadditions between Chlorosulfonyl Isocyanate and chiral vinyl ethers
European Journal of Organic Chemistry, 2002Co-Authors: Robert łysek, Bartlomiej Furman, Maciej Cierpucha, Barbara Grzeszczyk, łukasz Matyjasek, Marek ChmielewskiAbstract:Vinyl ethers 10, 23, and 33 were attached to Wang resin through the p-oxyphenylsulfonyl linker. The [2+2] cycloadditions between Chlorosulfonyl Isocyanate and the polymer-bound vinyl ethers 12, 24, and 34, followed by intramolecular alkylation of the β-lactam nitrogen atom, gave mixtures of the corresponding diastereomeric clavams 8/9 and 21/22 or the oxacephams 31/32, accompanied by the oxirane 7 or the oxetane 30, respectively. This cyclization/cleavage step was performed in the presence of the strong organic bases BEMP and DBU. The corresponding reaction sequences performed in solution provided the oxabicyclic β-lactams without the accompanying anhydrosugars. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)
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2 2 cycloaddition of Chlorosulfonyl Isocyanate to allenyl sugar ethers
Tetrahedron-asymmetry, 2000Co-Authors: Robert łysek, Bartlomiej Furman, Zbigniew Kaluza, Jadwiga Frelek, Kinga Suwinska, Zofia Urbanczyklipkowska, Marek ChmielewskiAbstract:Abstract The direction and magnitude of asymmetric induction in the [2+2] cycloaddition of Chlorosulfonyl Isocyanate to 3-O-allenyl-α- d -xylofuranoses was investigated. It is shown that gem terminal dimethylallenes react more readily than methyl free congeners. The configuration of adducts was established by X-ray and CD-spectroscopy of alkylidene cephams. A stereochemical model of the transition state for the [2+2] cycloaddition of Chlorosulfonyl Isocyanate and allenyl ethers is proposed, based on the lowest energy conformation of the cumulene.
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stereochemical model of 2 2 cycloaddition of Chlorosulfonyl Isocyanate to chiral vinyl ethers
Journal of The Chemical Society-perkin Transactions 1, 1999Co-Authors: Bartlomiej Furman, Zbigniew Kaluza, Piotr Krajewski, Rene Thurmer, Wolfgang Voelter, Lech Kozerski, Michael P Williamson, Marek ChmielewskiAbstract:A comparison of steady-state NOE coefficients measured for vinyl-substituted isopropyl ethers with conformations generated by a molecular mechanics program allowed a characterization of the most favorable ground state conformations. With high confidence it was possible to assign the lowest energy conformation to one which is characterized by a diastereo-zeroplane consisting of the s-trans vinyl group, the stereogenic center and the methyl group (Fig. 3). A stereochemical model of the transition state for [2+2]cycloaddition of Chlorosulfonyl Isocyanate and vinyl ethers is proposed, based on the lowest energy conformation derived from NOE coefficients, which agrees well with the experimental facts and provides a sound explanation of the direction of asymmetric induction.
In Su Kim - One of the best experts on this subject based on the ideXlab platform.
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total synthesis of codonopsinine via regioselective and diastereoselective amination using Chlorosulfonyl Isocyanate
Tetrahedron, 2017Co-Authors: Young Jae Choi, Sook Jin Park, In Su Kim, Yoo Chang Kim, Jun Min Jung, Yeon Su Kim, Young Hoon JungAbstract:Abstract The total synthesis of (−)-codonopsinine ( 1 ) from the readily available ( S )-3-chloropropan-1,2-diol is described. The key steps for the preparation of (−)-codonopsinine ( 1 ) involve the regioselective and diastereoselective amination of anti -1,2-dibenzyl ether 11 using Chlorosulfonyl Isocyanate and intramolecular amidomercuration to form the pyrrolidine ring. Notably, the reaction between anti -1,2-dibenzyl ether and Chlorosulfonyl Isocyanate in toluene at 0 °C produced the corresponding anti -1,2-amino alcohol 12a as a major product with excellent diastereoselectivity ( anti : syn = 29:1). This observation can be explained by the neighboring group participation leading to the retention of stereochemistry.
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divergent synthesis of aminocyclopentitol analogues via stereoselective amination of cyclic polybenzyl ether with Chlorosulfonyl Isocyanate
Synlett, 2015Co-Authors: Young Hoon Jung, Sook Jin Park, Yeon Ju Hong, Kyungtae Kang, Seung In Kim, So Yeon Kim, Jung Sang Park, In Su KimAbstract:The divergent synthesis of some novel aminocyclopentitol analogues was concisely achieved from readily available d -galactose via the highly diastereoselective amination of carbocyclic polybenzyl ether using Chlorosulfonyl Isocyanate, diastereoselective dihydroxylation, and epoxidation as the key steps.
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total synthesis of valienamine and 1 epi valienamine via a highly diastereoselective allylic amination of cyclic polybenzyl ether using Chlorosulfonyl Isocyanate
Tetrahedron, 2013Co-Authors: Seung In Kim, Sook Jin Park, In Su Kim, Hye Ran Yang, Reum A Baek, Young Hoon JungAbstract:Abstract The total synthesis of (+)-valienamine and (−)-1-epi-valienamine was concisely accomplished from readily available d -glucose via a highly diastereoselective amination of chiral benzylic ether using Chlorosulfonyl Isocyanate, intramolecular olefin metathesis, and diastereoselective reduction of cyclic enone using l -Selectride as the key steps.
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asymmetric formal synthesis of swainsonine by a highly regioselective and diastereoselective allylic amination using Chlorosulfonyl Isocyanate
European Journal of Organic Chemistry, 2013Co-Authors: Guang Ri Dong, Sook Jin Park, In Su Kim, Yong Rae Hong, Young Hoon JungAbstract:A concise asymmetric formal synthesis of (–)-swainsonine from readily available D-erythronolactone is described. The key steps include a highly diastereoselective amination of a chiral benzylic ether, which occurs with the retention of stereochemistry using Chlorosulfonyl Isocyanate, and a palladium-catalyzed decarboxylative N-allylation of an allyl carbamate.
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asymmetric total synthesis of indatraline via diastereoselective amination of chiral ethers using Chlorosulfonyl Isocyanate
Tetrahedron, 2013Co-Authors: Sang Hwi Lee, Sook Jin Park, In Su Kim, Young Hoon JungAbstract:A concise asymmetric total synthesis of (+)-indatraline from readily available cinnamic acid is described. The key steps include Corey's oxazaborolidine-catalyzed asymmetric carbonyl reduction and a highly stereoselective amination of chiral benzylic ether with retention of stereochemistry using Chlorosulfonyl Isocyanate.
Dale F Shellhamer - One of the best experts on this subject based on the ideXlab platform.
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nmr line broadening and transverse relaxation time measurements support a di radical intermediate for the reaction of Chlorosulfonyl Isocyanate with electron rich alkenes
Results in Chemistry, 2020Co-Authors: Dale F Shellhamer, Zachary J Beavis, Dakota L Brady, Marcela S Bucardo, Sarah L Elwin, Nicholas Fiorella, Leticia Gomez, Sara Van Horne, Marc C PerryAbstract:Abstract Line-broadening by NMR is an easy and fast method to detect radical intermediates in solution. Chlorosulfonyl Isocyanate reacts with electron-rich alkenes via a Single Electron Transfer pathway to give 1,4-diradical intermediates. The Triplet 1,4-diradical can change to the Singlet species at lower temperatures. Less reactive alkenes proceed via a concerted pathway.
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improved synthetic utility of a sluggish electrophile reaction of Chlorosulfonyl Isocyanate with unreactive and reactive alkenes
ChemInform, 2015Co-Authors: Dale F Shellhamer, Sarah L Elwin, Kelsey L Alexander, Summer A Bunting, Christine J Licata, Jacob C Milligan, Ryand Robinson, Danielle E Shipowick, Lincoln B Smith, Marc C PerryAbstract:The equilibrium between two separate reactants and a complex or SET intermediate formed by them shifts towards the unimolecular intermediate between -15 and 25°, therefore, the efficiency of the electrophile (II) is improved under the reaction conditions.
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improved synthetic utility of a sluggish electrophile reaction of Chlorosulfonyl Isocyanate with unreactive and reactive alkenes
Synthesis, 2015Co-Authors: Dale F Shellhamer, Sarah L Elwin, Kelsey L Alexander, Summer A Bunting, Christine J Licata, Jacob C Milligan, Ryand Robinson, Danielle E Shipowick, Lincoln B Smith, Marc C PerryAbstract:Chlorosulfonyl Isocyanate (CSI) is a sluggish electrophile in reactions with electron-deficient alkenes or with many monofluoroalkenes. The efficiency of these reactions is improved at temperatures between –15 and 25 °C because, at these temperatures, CSI and the alkene are in equilibrium with an intermediate. A unimolecular reaction of the intermediate at a temperature between –15 and 25 °C is more efficient than the bimolecular reaction of the dissociated reagents above room temperature. This finding provides a method for improving the reactions of CSI with unreactive alkenes.
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kinetic studies on the reaction of Chlorosulfonyl Isocyanate with monofluoroalkenes experimental evidence for both stepwise and concerted mechanisms and a pre equilibrium complex on the reaction pathway
Journal of Organic Chemistry, 2013Co-Authors: Dale F Shellhamer, Marc C Perry, Kelli R Hickle, David J Vandenbroek, Summer A Bunting, Jacob C Milligan, Danielle E Shipowick, Lincoln B Smith, Parker C Horn, Jerry A BoatzAbstract:Chlorosulfonyl Isocyanate (CSI) is reported to react with hydrocarbon alkenes by a stepwise dipolar pathway to give N-Chlorosulfonyl-β-lactams that are readily reduced to β-lactams. Substitution of a vinyl hydrogen for a vinyl fluorine changes the dynamics for reaction with CSI so that a concerted pathway is favored. Rate constants were measured for reactions of CSI with monofluoroalkenes and some hydrocarbon alkenes. Activation parameters for two hydrocarbon alkenes and two monofluoroalkenes support this change in mechanism. A plot generated from the natural log of rate constants vs ionization potentials (IP) indicates that fluoroalkenes with IP values >8.9 eV react by a concerted process. Electron-rich monofluoroalkenes with IP values <8.5 eV were found to react by a single-electron transfer (SET) pathway. Hydrocarbon alkenes were also found to react by this dipolar stepwise SET intermediate rather than the previously accepted stepwise dipolar pathway. Data support a pre-equilibrium complex on the react...
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kinetic data and quantum chemical calculation studies on the stepwise vs concerted pathways for reaction of Chlorosulfonyl Isocyanate reactions with monofluoroalkenes
2013Co-Authors: Dale F Shellhamer, Jacob C Milligan, Danielle E Shipowick, Lincoln B Smith, Jerry A BoatzAbstract:Abstract : Chlorosulfonyl Isocyanate (CSI) is known to react with hydrocarbon alkenes by a stepwise pathway. Kinetic studies and quantum chemical calculations show that (CSI) reacts by a concerted process with monofluoroalkenes that have a calculated vertical ionization potential (IP) value 8.9 eV. Monofluoroalkenes however, with IP values 8.5 eV react with CSI by a stepwise process similar to hydrocarbon alkenes. Kinetic data and quantum chemical calculations also support a pre-equilibrium complex on the reaction pathway just before the stepwise or concerted kinetic transition states. The synthetic utility of CSI reactions with unreactive hydrocarbon and monofluoroalkenes is enhanced by running the reactions at a lower temperature where the pre-equilibrium is shifted toward the complex.
Jerry A Boatz - One of the best experts on this subject based on the ideXlab platform.
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kinetic studies on the reaction of Chlorosulfonyl Isocyanate with monofluoroalkenes experimental evidence for both stepwise and concerted mechanisms and a pre equilibrium complex on the reaction pathway
Journal of Organic Chemistry, 2013Co-Authors: Dale F Shellhamer, Marc C Perry, Kelli R Hickle, David J Vandenbroek, Summer A Bunting, Jacob C Milligan, Danielle E Shipowick, Lincoln B Smith, Parker C Horn, Jerry A BoatzAbstract:Chlorosulfonyl Isocyanate (CSI) is reported to react with hydrocarbon alkenes by a stepwise dipolar pathway to give N-Chlorosulfonyl-β-lactams that are readily reduced to β-lactams. Substitution of a vinyl hydrogen for a vinyl fluorine changes the dynamics for reaction with CSI so that a concerted pathway is favored. Rate constants were measured for reactions of CSI with monofluoroalkenes and some hydrocarbon alkenes. Activation parameters for two hydrocarbon alkenes and two monofluoroalkenes support this change in mechanism. A plot generated from the natural log of rate constants vs ionization potentials (IP) indicates that fluoroalkenes with IP values >8.9 eV react by a concerted process. Electron-rich monofluoroalkenes with IP values <8.5 eV were found to react by a single-electron transfer (SET) pathway. Hydrocarbon alkenes were also found to react by this dipolar stepwise SET intermediate rather than the previously accepted stepwise dipolar pathway. Data support a pre-equilibrium complex on the react...
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kinetic data and quantum chemical calculation studies on the stepwise vs concerted pathways for reaction of Chlorosulfonyl Isocyanate reactions with monofluoroalkenes
2013Co-Authors: Dale F Shellhamer, Jacob C Milligan, Danielle E Shipowick, Lincoln B Smith, Jerry A BoatzAbstract:Abstract : Chlorosulfonyl Isocyanate (CSI) is known to react with hydrocarbon alkenes by a stepwise pathway. Kinetic studies and quantum chemical calculations show that (CSI) reacts by a concerted process with monofluoroalkenes that have a calculated vertical ionization potential (IP) value 8.9 eV. Monofluoroalkenes however, with IP values 8.5 eV react with CSI by a stepwise process similar to hydrocarbon alkenes. Kinetic data and quantum chemical calculations also support a pre-equilibrium complex on the reaction pathway just before the stepwise or concerted kinetic transition states. The synthetic utility of CSI reactions with unreactive hydrocarbon and monofluoroalkenes is enhanced by running the reactions at a lower temperature where the pre-equilibrium is shifted toward the complex.
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Kinetic Studies on the Reaction of Chlorosulfonyl Isocyanate with Monofluoroalkenes: Experimental Evidence for Both Stepwise and Concerted Mechanisms and a Pre-equilibrium Complex on the Reaction Pathway
2013Co-Authors: Dale F Shellhamer, Marc C Perry, Kelli R Hickle, David J Vandenbroek, Summer A Bunting, Jacob C Milligan, Danielle E Shipowick, Lincoln B Smith, Parker C. Horn, Jerry A BoatzAbstract:Chlorosulfonyl Isocyanate (CSI) is reported to react with hydrocarbon alkenes by a stepwise dipolar pathway to give N-Chlorosulfonyl-β-lactams that are readily reduced to β-lactams. Substitution of a vinyl hydrogen for a vinyl fluorine changes the dynamics for reaction with CSI so that a concerted pathway is favored. Rate constants were measured for reactions of CSI with monofluoroalkenes and some hydrocarbon alkenes. Activation parameters for two hydrocarbon alkenes and two monofluoroalkenes support this change in mechanism. A plot generated from the natural log of rate constants vs ionization potentials (IP) indicates that fluoroalkenes with IP values >8.9 eV react by a concerted process. Electron-rich monofluoroalkenes with IP values
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reaction of Chlorosulfonyl Isocyanate with fluorosubstituted alkenes evidence of a concerted pathway
Journal of Organic Chemistry, 2010Co-Authors: Dale F Shellhamer, Kevyn J Davenport, Danielle M Hassler, Kelli R Hickle, Jacob J Thorpe, David J Vandenbroek, Victor L Heasley, Jerry A Boatz, Arnold L Reingold, Curtis E MooreAbstract:Concerted reactions are indicated for the electrophilic addition of Chlorosulfonyl Isocyanate with monofluoroalkenes. A vinyl fluorine atom on an alkene raises the energy of a stepwise transition state more than the energy of the competing concerted pathway. This energy shift induces CSI to react with monofluoroalkenes by a one-step process. The low reactivity of CSI with monofluoroalkenes, stereospecific reactions, the absence of 2:1 uracil products with neat fluoroalkenes, and quantum chemical calculations support a concerted pathway.
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reaction of Chlorosulfonyl Isocyanate csi with fluorosubstituted alkenes evidence of a concerted pathway for reaction of csi with fluorosubstituted alkenes preprint
2010Co-Authors: Dale F Shellhamer, Kevyn J Davenport, Danielle M Hassler, Kelli R Hickle, Jacob J Thorpe, David J Vandenbroek, Victor L Heasley, Jerry A Boatz, Arnold L Reingold, Curtis E MooreAbstract:Abstract : Concerted reactions are indicated for the electrophilic addition of Chlorosulfonyl Isocyanate with monofluoroalkenes. A vinyl fluorine atom on an alkene raises the energy of a step-wise transition state more than the energy of the competing concerted pathway. This energy shift induces CSI to react with monofluoroalkenes by a one-step process. The low reactivity of CSI with monofluoroalkenes, stereospecific reactions, the absence of 2:1 uracil products with neat fluoroalkenes and quantum chemical calculations support a concerted pathway.