1
|
Byrne PA, Kobayashi S, Würthwein EU, Ammer J, Mayr H. Why Are Vinyl Cations Sluggish Electrophiles? J Am Chem Soc 2017; 139:1499-1511. [PMID: 28040896 DOI: 10.1021/jacs.6b10889] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The kinetics of the reactions of the vinyl cations 2 [Ph2C═C+-(4-MeO-C6H4)] and 3 [Me2C═C+-(4-MeO-C6H4)] (generated by laser flash photolysis) with diverse nucleophiles (e.g., pyrroles, halide ions, and solvents containing variable amounts of water or alcohol) have been determined photometrically. It was found that the reactivity order of the nucleophiles toward these vinyl cations is the same as that toward diarylcarbenium ions (benzhydrylium ions). However, the reaction rates of vinyl cations are affected only half as much by variation of the nucleophiles as those of the benzhydrylium ions. For that reason, the relative reactivities of vinyl cations and benzhydrylium ions depend strongly on the nature of the nucleophiles. It is shown that vinyl cations 2 and 3 react, respectively, 227 and 14 times more slowly with trifluoroethanol than the parent benzhydrylium ion (Ph)2CH+, even though in solvolysis reactions (80% aqueous ethanol at 25 °C) the vinyl bromides leading to 2 and 3 ionize much more slowly (half-lives 1.15 yrs and 33 days) than (Ph)2CH-Br (half-life 23 s). The origin of this counterintuitive phenomenon was investigated by high-level MO calculations. We report that vinyl cations are not exceptionally high energy intermediates, and that high intrinsic barriers for the sp2 ⇌ sp rehybridizations account for the general phenomenon that vinyl cations are formed slowly by solvolytic cleavage of vinyl derivatives, and are also consumed slowly by reactions with nucleophiles.
Collapse
Affiliation(s)
- Peter A Byrne
- Department Chemie, Ludwig-Maximilians-Universität München , Butenandtstrasse 5-13, 81377 München, Germany
| | - Shinjiro Kobayashi
- Department Chemie, Ludwig-Maximilians-Universität München , Butenandtstrasse 5-13, 81377 München, Germany
| | - Ernst-Ulrich Würthwein
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität , 48149 Münster, Germany
| | - Johannes Ammer
- Department Chemie, Ludwig-Maximilians-Universität München , Butenandtstrasse 5-13, 81377 München, Germany
| | - Herbert Mayr
- Department Chemie, Ludwig-Maximilians-Universität München , Butenandtstrasse 5-13, 81377 München, Germany
| |
Collapse
|
2
|
Xu D, Rios R, Ba F, Ma D, Gu G, Ding A, Kuang Y, Guo H. Photoinduced Intramolecular Haloarylation and Hydroarylation of Alkynes. ASIAN J ORG CHEM 2016. [DOI: 10.1002/ajoc.201600232] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Dawen Xu
- Department of Chemistry; Fudan University; 220 Handan Road Shanghai 200433 P. R. China
| | - Ramon Rios
- School of Chemistry; University of Southampton; Southampton SO17 1BJ UK
| | - Feifei Ba
- Department of Chemistry; Fudan University; 220 Handan Road Shanghai 200433 P. R. China
| | - Dongmei Ma
- Department of Chemistry; Fudan University; 220 Handan Road Shanghai 200433 P. R. China
| | - Guangxin Gu
- Department of Chemistry; Fudan University; 220 Handan Road Shanghai 200433 P. R. China
| | - Aishun Ding
- Department of Chemistry; Fudan University; 220 Handan Road Shanghai 200433 P. R. China
| | - Yunyan Kuang
- Department of Chemistry; Fudan University; 220 Handan Road Shanghai 200433 P. R. China
- Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules; Shanghai Institute of Organic Chemistry; Chinese Academy of Sciences; Shanghai 200032 P. R. China
| | - Hao Guo
- Department of Chemistry; Fudan University; 220 Handan Road Shanghai 200433 P. R. China
- Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules; Shanghai Institute of Organic Chemistry; Chinese Academy of Sciences; Shanghai 200032 P. R. China
| |
Collapse
|
3
|
van Dorp JWJ, Lodder G. Substituent Effects on the Photogeneration and Selectivity of Triaryl Vinyl Cations. J Org Chem 2008; 73:5416-28. [DOI: 10.1021/jo800687z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jan Willem J. van Dorp
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Gerrit Lodder
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| |
Collapse
|
4
|
Barros JC, de Souza ALF, de Lima PG, da Silva JFM, Antunes OAC. Selectivity studies in the reaction between iodobenzene and phenylacetylene: Sonogashira coupling vs hydroarylation. Appl Organomet Chem 2008. [DOI: 10.1002/aoc.1385] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
5
|
Görner H, Kuhn HJ. Cis-TransPhotoisomerization of Stilbenes and Stilbene-Like Molecules. ADVANCES IN PHOTOCHEMISTRY 2007. [DOI: 10.1002/9780470133507.ch1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|
6
|
Gronheid R, Zuilhof H, Hellings MG, Cornelisse J, Lodder G. Photochemical generation of a primary vinyl cation from (E)-bromostyrene: mechanisms of formation and reaction. J Org Chem 2003; 68:3205-15. [PMID: 12688792 DOI: 10.1021/jo0264877] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photochemistry of (E)-bromostyrene was investigated to determine the nature of the product-forming intermediates and to clarify the mechanism of formation of vinylic cations and vinylic radicals. Both a cation- and a radical-derived product are formed, and the ionic origin of the former product is demonstrated by significant scrambling of the label, starting from specifically deuterated (E)-bromostyrene. MO calculations show that the isolated incipient primary vinyl cation is not a metastable species, but that specific interaction with a counterion in combination with a polar environment makes it metastable. The effects of variation of the wavelength of irradiation, solvent polarity, temperature, and isotopic substitution all agree with a mechanism of direct heterolytic C-Br bond cleavage producing an ion pair followed by formation of a radical pair via electron transfer. The vinylic cation is proposed to stem directly from the indirectly populated lowest excited singlet state of bromostyrene with an energy of activation of 6.7 kcal/mol. Branching between proton loss and electron transfer in the resulting ion pair determines the ratio of cation- to radical-derived product. The E/Z-isomerization occurs in a separate process and does not involve C-Br bond cleavage.
Collapse
Affiliation(s)
- Roel Gronheid
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | | | | | | | | |
Collapse
|
7
|
Liron F, Gervais M, Peyrat JF, Alami M, Brion JD. Palladium-catalyzed stereoselective synthesis of E- and Z-1,1-diaryl or triarylolefins. Tetrahedron Lett 2003. [DOI: 10.1016/s0040-4039(03)00459-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
8
|
Palladium-catalyzed reactions of aryl iodides with trimethylsilylacetylenes and disubstituted alkynes: the synthesis of diarylacetylenes and triarylethylenes. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(01)00758-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
9
|
A facile synthetic route to a third-generation dendrimer with generation-specific functional aryl bromides. Org Lett 2000; 2:1645-8. [PMID: 10841500 DOI: 10.1021/ol005972q] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis of three third-generation dendrimers that selectively carry one aryl bromide functional group in the first, second, or third generation, respectively, is described. These functions, regardless of their location, can be chemically modified by Suzuki cross-coupling chemistry with p-tert-butylbenzene boronic ester.
Collapse
|
10
|
Galli C, Gentili P, Guarnieri A, Kobayashi S, Zvi Rappoport. Competition of Mechanisms in the Photochemical Cleavage of the C−X Bond of Aryl-Substituted Vinyl Halides. J Org Chem 1998. [DOI: 10.1021/jo981164p] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Carlo Galli
- Dipartimento di Chimica, Università “La Sapienza”, 00185 Roma, Italy, Institute for Fundamental Research of Organic Chemistry, Kyushu University, Fukuoka 812, Japan, and Department of Organic Chemistry, The Hebrew University, Jerusalem 91904, Israel
| | - Patrizia Gentili
- Dipartimento di Chimica, Università “La Sapienza”, 00185 Roma, Italy, Institute for Fundamental Research of Organic Chemistry, Kyushu University, Fukuoka 812, Japan, and Department of Organic Chemistry, The Hebrew University, Jerusalem 91904, Israel
| | - Alessandra Guarnieri
- Dipartimento di Chimica, Università “La Sapienza”, 00185 Roma, Italy, Institute for Fundamental Research of Organic Chemistry, Kyushu University, Fukuoka 812, Japan, and Department of Organic Chemistry, The Hebrew University, Jerusalem 91904, Israel
| | - Shinjiro Kobayashi
- Dipartimento di Chimica, Università “La Sapienza”, 00185 Roma, Italy, Institute for Fundamental Research of Organic Chemistry, Kyushu University, Fukuoka 812, Japan, and Department of Organic Chemistry, The Hebrew University, Jerusalem 91904, Israel
| | - Zvi Rappoport
- Dipartimento di Chimica, Università “La Sapienza”, 00185 Roma, Italy, Institute for Fundamental Research of Organic Chemistry, Kyushu University, Fukuoka 812, Japan, and Department of Organic Chemistry, The Hebrew University, Jerusalem 91904, Israel
| |
Collapse
|
11
|
|
12
|
|
13
|
Destabilized vinyl cations. An MO study of the influence of electron-withdrawing substituents. Tetrahedron Lett 1994. [DOI: 10.1016/s0040-4039(00)76527-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
14
|
|
15
|
Andraos J, Kresge AJ, Obraztsov PA. Solvent and secondary substrate isotope effects on the acid-catalyzed ketonization of acetophenone enol in aqueous solution. J PHYS ORG CHEM 1992. [DOI: 10.1002/poc.610050607] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
16
|
van Ginkel FI, Cornelisse J, Lodder G. Kinetic treatment of photochemically induced concurrent isotope exchange and product formation. J Photochem Photobiol A Chem 1991. [DOI: 10.1016/1010-6030(91)90015-l] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|