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Lapi A, D'Alfonso C, Del Giacco T, Lanzalunga O. Competition Between C α -S and C α -C β Bond Cleavage in β-Hydroxysulfoxides Cation Radicals Generated by Photoinduced Electron Transfer †. Photochem Photobiol 2021; 97:1310-1321. [PMID: 33998681 PMCID: PMC9290654 DOI: 10.1111/php.13455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/03/2021] [Accepted: 05/11/2021] [Indexed: 11/28/2022]
Abstract
A kinetic and product study of the 3‐cyano‐N‐methyl‐quinolinium photoinduced monoelectronic oxidation of a series of β‐hydroxysulfoxides has been carried out to investigate the competition between Cα‐S and Cα‐Cβ bond cleavage within the corresponding cation radicals. Laser flash photolysis experiments unequivocally established the formation of sulfoxide cation radicals showing their absorption band (λmax ≈ 520 nm) and that of 3‐CN‐NMQ• (λmax ≈ 390 nm). Steady‐state photolysis experiments suggest that, in contrast to what previously observed for alkyl phenyl sulfoxide cation radicals that exclusively undergo Cα‐S bond cleavage, the presence of a β‐hydroxy group makes, in some cases, the Cα‐Cβ scission competitive. The factors governing this competition seem to depend on the relative stability of the fragments formed from the two bond scissions. Substitution of the β‐OH group with ‐OMe did not dramatically change the reactivity pattern of the cation radicals thus suggesting that the observed favorable effect of the hydroxy group on the Cα‐Cβ bond cleavage mainly resides on its capability to stabilize the carbocation formed upon this scission.
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Affiliation(s)
- Andrea Lapi
- Dipartimento di Chimica, Universita` degli Studi di Roma "La Sapienza", Rome, Italy.,Istituto per i Sistemi Biologici (ISB-CNR), Sede Secondaria di Roma-Meccanismi di Reazione, c/o Dipartimento di Chimica, Universita` degli Studi di Roma "La Sapienza", Rome, Italy
| | - Claudio D'Alfonso
- Dipartimento di Chimica, Universita` degli Studi di Roma "La Sapienza", Rome, Italy
| | - Tiziana Del Giacco
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy.,Centro di Eccellenza Materiali Innovativi Nanostrutturati (CEMIN), Università di Perugia, Perugia, Italy
| | - Osvaldo Lanzalunga
- Dipartimento di Chimica, Universita` degli Studi di Roma "La Sapienza", Rome, Italy.,Istituto per i Sistemi Biologici (ISB-CNR), Sede Secondaria di Roma-Meccanismi di Reazione, c/o Dipartimento di Chimica, Universita` degli Studi di Roma "La Sapienza", Rome, Italy
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Photocatalytic Deoxygenation of Sulfoxides Using Visible Light: Mechanistic Investigations and Synthetic Applications. ACS Catal 2020; 10:5814-5820. [PMID: 32582464 PMCID: PMC7304878 DOI: 10.1021/acscatal.0c00690] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/15/2020] [Indexed: 12/25/2022]
Abstract
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The
photocatalytic deoxygenation of sulfoxides to generate sulfides
facilitated by either Ir[(dF(CF3)ppy)2(dtbbpy)]PF6 or fac-Ir(ppy)3 is reported.
Mechanistic studies indicate that a radical chain mechanism operates,
which proceeds via a phosphoranyl radical generated from a radical/polar
crossover process. Initiation of the radical chain was found to proceed
via two opposing photocatalytic quenching mechanisms, offering complementary
reactivity. The mild nature of the radical deoxygenation process enables
the reduction of a wide range of functionalized sulfoxides, including
those containing acid-sensitive groups, in typically high isolated
yields.
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3
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Sulfur Radicals and Their Application. Top Curr Chem (Cham) 2018; 376:22. [DOI: 10.1007/s41061-018-0197-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/11/2018] [Indexed: 12/11/2022]
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4
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Azizi N, Edrisi M. Biodegradable choline hydroxide promoted environmentally benign thiolysis of epoxides. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2015.12.080] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Bettoni M, Del Giacco T, Stradiotto M, Elisei F. Photoinduced One-Electron Oxidation of Benzyl Methyl Sulfides in Acetonitrile: Time-Resolved Spectroscopic Evidence for a Thionium Ion Intermediate. J Org Chem 2015; 80:8001-8. [DOI: 10.1021/acs.joc.5b01052] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marta Bettoni
- Dipartimento
di Ingegneria Civile ed Ambientale, ‡Dipartimento di Chimica, Biologia
e Biotecnologie, and §Centro di Eccellenza Materiali Innovativi Nanostrutturati (CEMIN), Università di Perugia, 06123 Perugia, Italy
| | - Tiziana Del Giacco
- Dipartimento
di Ingegneria Civile ed Ambientale, ‡Dipartimento di Chimica, Biologia
e Biotecnologie, and §Centro di Eccellenza Materiali Innovativi Nanostrutturati (CEMIN), Università di Perugia, 06123 Perugia, Italy
| | - Marina Stradiotto
- Dipartimento
di Ingegneria Civile ed Ambientale, ‡Dipartimento di Chimica, Biologia
e Biotecnologie, and §Centro di Eccellenza Materiali Innovativi Nanostrutturati (CEMIN), Università di Perugia, 06123 Perugia, Italy
| | - Fausto Elisei
- Dipartimento
di Ingegneria Civile ed Ambientale, ‡Dipartimento di Chimica, Biologia
e Biotecnologie, and §Centro di Eccellenza Materiali Innovativi Nanostrutturati (CEMIN), Università di Perugia, 06123 Perugia, Italy
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Cyr D, Das P. Kinetics of C–C and C–H Bond Cleavage in Phenyl Alkane Radical Cations Generated by Photoinduced Electron Transfer. J Phys Chem A 2014; 118:11155-67. [DOI: 10.1021/jp508556z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Douglas Cyr
- Physical
Sciences Department, Cameron University, Lawton, Oklahoma 73505, United States
| | - Paritosh Das
- Physical
Sciences Department, Cameron University, Lawton, Oklahoma 73505, United States
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Collado D, Perez-Inestrosa E. Regioselective Photochemical C-OMe Bond Formation Initiated by One-Electron Transfer and N-OMe Bond Fragmentation in Electron Donor-Acceptor Systems. European J Org Chem 2012. [DOI: 10.1002/ejoc.201101595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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8
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Lanzalunga O, Lapi A. Recent photo- and radiation chemical studies of sulfur radical cations. J Sulphur Chem 2011. [DOI: 10.1080/17415993.2011.619536] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Osvaldo Lanzalunga
- a Dipartimento di Chimica and IMC-CNR, Sezione Meccanismi di Reazione , Università “La Sapienza” , P.le A. Moro, 5 I-00185 , Rome , Italy
| | - Andrea Lapi
- a Dipartimento di Chimica and IMC-CNR, Sezione Meccanismi di Reazione , Università “La Sapienza” , P.le A. Moro, 5 I-00185 , Rome , Italy
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9
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Baciocchi E, Bettoni M, Del Giacco T, Lanzalunga O, Mazzonna M, Mencarelli P. Structure and C−S Bond Cleavage in Aryl 1-Methyl-1-arylethyl Sulfide Radical Cations. J Org Chem 2010; 76:573-82. [DOI: 10.1021/jo102086f] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Enrico Baciocchi
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università di Roma La Sapienza, P.le A. Moro 5, 00185 Rome, Italy
| | - Marta Bettoni
- Dipartimento di Chimica and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia, via Elce di Sotto 8, 06123 Perugia, Italy
| | - Tiziana Del Giacco
- Dipartimento di Chimica and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia, via Elce di Sotto 8, 06123 Perugia, Italy
| | - Osvaldo Lanzalunga
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università di Roma La Sapienza, P.le A. Moro 5, 00185 Rome, Italy
| | - Marco Mazzonna
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università di Roma La Sapienza, P.le A. Moro 5, 00185 Rome, Italy
| | - Paolo Mencarelli
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università di Roma La Sapienza, P.le A. Moro 5, 00185 Rome, Italy
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Baciocchi E, Del Giacco T, Lanzalunga O, Mencarelli P, Procacci B. Photosensitized Oxidation of Alkyl Phenyl Sulfoxides. C−S Bond Cleavage in Alkyl Phenyl Sulfoxide Radical Cations. J Org Chem 2008; 73:5675-82. [DOI: 10.1021/jo801088n] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Enrico Baciocchi
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Sapienza Università di Roma, P.le A. Moro 5, 00185 Rome, Italy, and Dipartimento di Chimica and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia, via Elce di sotto 8, 06123 Perugia, Italy
| | - Tiziana Del Giacco
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Sapienza Università di Roma, P.le A. Moro 5, 00185 Rome, Italy, and Dipartimento di Chimica and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia, via Elce di sotto 8, 06123 Perugia, Italy
| | - Osvaldo Lanzalunga
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Sapienza Università di Roma, P.le A. Moro 5, 00185 Rome, Italy, and Dipartimento di Chimica and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia, via Elce di sotto 8, 06123 Perugia, Italy
| | - Paolo Mencarelli
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Sapienza Università di Roma, P.le A. Moro 5, 00185 Rome, Italy, and Dipartimento di Chimica and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia, via Elce di sotto 8, 06123 Perugia, Italy
| | - Barbara Procacci
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Sapienza Università di Roma, P.le A. Moro 5, 00185 Rome, Italy, and Dipartimento di Chimica and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia, via Elce di sotto 8, 06123 Perugia, Italy
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11
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C–S bond cleavage in the sensitized photooxygenation of tert-alkyl phenyl sulfides. The role of superoxide anion. Tetrahedron 2006. [DOI: 10.1016/j.tet.2005.09.154] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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12
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Baciocchi E, Del Giacco T, Gerini MF, Lanzalunga O. Rates of C−S Bond Cleavage in tert-Alkyl Phenyl Sulfide Radical Cations. Org Lett 2006; 8:641-4. [PMID: 16468731 DOI: 10.1021/ol052834y] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] Radical cations of tert-alkyl phenyl sulfides 1-4 have been generated photochemically in MeCN in the presence of the N-methoxyphenanthridinium cation (MeOP(+)), and the rates of C-S bond cleavage have been determined by laser flash photolysis.
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Affiliation(s)
- Enrico Baciocchi
- Dipartimento di Chimica, Università La Sapienza and IMC-CNR, Sezione Meccanismi di Reazione, P.le A. Moro, 5 I-00185 Rome, Italy.
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13
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Baciocchi E, Bietti M, Lanzalunga O. Fragmentation reactions of radical cations. J PHYS ORG CHEM 2006. [DOI: 10.1002/poc.1096] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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14
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Baciocchi E, Del Giacco T, Elisei F, Lapi A. Sulfur Radical Cations. Kinetic and Product Study of the Photoinduced Fragmentation Reactions of (Phenylsulfanylalkyl)trimethylsilanes and Phenylsulfanylacetic Acid Radical Cations. J Org Chem 2005; 71:853-60. [PMID: 16438494 DOI: 10.1021/jo051145x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Laser and steady-state photolysis, sensitized by NMQ+, of PhSCH(R)X 1-4 (R = H, Ph; X =SiMe3, CO2H) was carried out in CH3CN. The formation of 1+*-4+* was clearly shown. All radical cations undergo a fast first-order fragmentation reaction involving C-Si bond cleavage with 1+* and 2+* and C-C bond cleavage with 3+* and 4+*. The desilylation reaction of 1+* and 2+* was nucleophilically assisted, and the decarboxylation rates of 3+* and 4+* increased in the presence of H2O. A deuterium kinetic isotope effect of 2.0 was observed when H2O was replaced by D2O. Pyridines too were found to accelerate the decarboxylation rate of 3+* and 4+*. The rate increase, however, was not a linear function of the base concentration, but a plateau was reached. A fast and reversible formation of a H-bonded complex between the radical cation and the base is suggested, which undergoes C-C bond cleavage. It is probable that the H-bond complex undergoes first a rate determining proton-coupled electron transfer forming a carboxyl radical that then loses CO2. The steady-state photolysis study showed that PhSCH3 was the exclusive product formed from 1 and 3 whereas [PhS(Ph)CH-]2 was the only product with 3 and 4.
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Affiliation(s)
- Enrico Baciocchi
- Dipartimento di Chimica, Università La Sapienza, Piazzale A. Moro 5, 00185 Rome, Italy.
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