Selectivity in the Chemistry of Oxygen-Centered Radicals - The Formation of Carbon-Oxygen Bonds

Jens  Hartung; Thomas  Gottwald; Kristina  Špehar

doi:10.1055/s-2002-33335

REVIEW

Selectivity in the Chemistry of Oxygen-Centered Radicals - The Formation of Carbon-Oxygen Bonds

Jens Hartung*, Thomas Gottwald, Kristina Špehar
Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
Fax: +49(931)8884606; e-Mail: hartung@chemie.uni-wuerzburg.de;

Abstract

Alle Artikel dieser Rubrik

Abstract

In recent years, powerful new methods for the generation of alkoxyl radicals under mild and neutral conditions have been developed. This progress has led to a thorough investigation of most O-radical elementary reactions. Today, sufficiently reliable thermodynamic and kinetic data are available either from experimental or from theoretical studies in order to predict alkoxyl radical reactivities and selectivities in synthesis. For instance, alkoxyl radicals readily add to carbon-carbon and carbon-nitrogen double bonds. Due to generally low activation barriers and strongly negative reaction enthalpies, inter- and intramolecular addition reactions proceed under kinetic control and are associated with high rate constants. Nevertheless, intramolecular 5-exo-trig additions, i.e. cyclizations, proceed with an astonishing degree of diastereoselectivity and often provide complementary selectivities if compared to commonly used methods such as the bromine cyclization of alkenols. Therefore, several useful applications of O-radical cyclizations in the synthesis of functionalized tetrahydrofurans have been discovered in the last few years. A second major reaction channel of alkoxyl radicals is associated with the homolysis of a β-C-C bond. This fragmentation proceeds under thermodynamic control and affords a carbonyl compound besides an alkyl radical from the starting alkoxyl radical. Regioselectivities for C-C bond homolysis may be predicted by considering strain release (cyclic carbon framework) and the stability of the newly formed carbon radical (cyclic and open chain carbon skeletons). The third major group of alkoxyl radical-based transformations are connected with homolytic substitutions such as intramolecular 1,5-hydrogen shifts which have been applied with considerable success to remote functionalization reactions. In view of the diversity of alkoxyl radical reactions it is the aim of this review to organize basic principles of this type of chemistry and to present its latest useful application in organic synthesis.

1 Introduction
2 General Aspects
3 Elementary Reactions
4 Generation of Oxygen-Centered Radicals and their
Application in Chain Reactions
5 Addition of O-Radicals to Multiple Bonds
5.1 Intramolecular Addition to Carbon Carbon Double Bonds
5.2 Intermolecular Addition to Double Bonds
6 Formation of Carbonyl Compounds (β-C-C Cleavage)
7 Rearrangements
8 Hydrogen Abstractions: Remote Functionalizations and
Subsequent Nucleophilic Transformations
9 Summary and Perspectives

Key words

addition - alkoxyl radical - cyclization - fragmentation - hydrogen atom transfer - natural products - rearrangement - stereoselective synthesis

Volltext

Referenzen

References

<A NAME="RE06902SS-1A">1a</A> Sawyer DT. Oxygen Chemistry Oxford University Press; Oxford: 1991.

<A NAME="RE06902SS-1B">1b</A> Ochai E.-I. J. Chem. Educ. 1993, 70: 128

<A NAME="RE06902SS-1C">1c</A> Nuhn P. Naturstoffchemie 3rd Ed.: S. Hirzel Verlag; Stuttgart: 1997. p.38-41

<A NAME="RE06902SS-1D">1d</A> Wayne RP. Chemistry of Atmospheres 2nd Ed.: Oxford University Press; Oxford: 1991. p.208-275

<A NAME="RE06902SS-2A">2a</A> Went FW. Nature (London) 1960, 187: 641

<A NAME="RE06902SS-2B">2b</A> Review: Graedel TE. Geophys. Space Phys. 1979, 17: 937

<A NAME="RE06902SS-2C">2c</A> Rinne J. Hakola H. Laurila T. Rannik U. Atmos. Environ. 2000, 34: 1099

<A NAME="RE06902SS-3A">3a</A> Trainer M. Williams EJ. Parrish DD. Buhr MP. Allwine EJ. Westberg HH. Fehsenfeld FC. Liu SC. Nature (London) 1987, 329: 705

<A NAME="RE06902SS-3B">3b</A> Lei W. Zhang R. J. Chem. Phys. A 2001, 105: 3808

<A NAME="RE06902SS-4">4</A> Betteridge DJ. Metabolism 2000, 49: 3

<A NAME="RE06902SS-5">5</A> Fukuto J. Ignarro LJ. Acc. Chem. Res. 1997, 30: 149

<A NAME="RE06902SS-6">6</A> Leffler JE. An Introduction to Free Radicals Wiley; New York: 1993.

<A NAME="RE06902SS-7A">7a</A> Herz W. Ligon RC. Turner JA. Blount JF. J. Org. Chem. 1977, 42: 1885

<A NAME="RE06902SS-7B">7b</A> Ullrich V. Brugger R. Angew. Chem., Int. Ed. Engl. 1994, 33: 1911 ; Angew. Chem. 1994, 106, 1987

<A NAME="RE06902SS-8A">8a</A> Whittaker MM. Whittaker JW. J. Biol. Chem. 1990, 265: 9610

<A NAME="RE06902SS-8B">8b</A> Chaudhuri P. Hess M. Müller J. Hildenbrand K. Bill E. Weyhermüller T. Wieghardt K. J. Am. Chem. Soc. 1999, 121: 9599

<A NAME="RE06902SS-9">9</A> Janes SM. Mu D. Wemmes D. Smith AJ. Kaus S. Maltby D. Burlingame AL. Klinman JP. Science 1990, 248: 981

<A NAME="RE06902SS-10A">10a</A> Norlund P. Sjöberg B.-M. Eklund H. Nature (London) 1990, 345: 593

<A NAME="RE06902SS-10B">10b</A> Stubbe J. van der Donk WA. Chem. Rev. 1998, 98: 705

<A NAME="RE06902SS-11">11</A> Lee C.-Y. Cardiovasc. Res. 1994, 28: 729

<A NAME="RE06902SS-12A">12a</A> Riley PA. Int. J. Radiat. Biol. 1994, 65: 27

<A NAME="RE06902SS-12B">12b</A> Lee SH. Blair IA. Trends Cardiovasc. Med. 2001, 11: 148

<A NAME="RE06902SS-13">13</A> Halliwell B. Gutteridge JMC. Free Radicals in Biology and Medicine 3rd Ed.: Oxford University Press; Oxford: 1999.

<A NAME="RE06902SS-14">14</A> Giese B. Porter N. Curran DP. Stereochemistry of Radical Reactions VCH; Weinheim: 1995.

<A NAME="RE06902SS-15">15</A> Wieland H. Ber. Dtsch. Chem. Ges. 1911, 44: 2550

<A NAME="RE06902SS-16A">16a</A> Fenton HJH. J. Chem. Soc. 1894, 65: 899

<A NAME="RE06902SS-16B">16b</A> Walling C. Acc. Chem. Res. 1975, 8: 125

<A NAME="RE06902SS-17">17</A> Buda F. Ensing B. Gribnau MCM. Baerends EJ. Chem.-Eur. J. 2001, 7: 2775

<A NAME="RE06902SS-18A">18a</A> Micovic VM. Mamuzic RI. Jeremic D. Mihailovic MLj. Tetrahedron 1964, 20: 2279

<A NAME="RE06902SS-18B">18b</A> Mihailovic MLJ. Andrejevic V. Jakovljevic M. Jeremic D. Stojiljkovic A. Partch RE. J. Chem. Soc., Chem. Commun. 1970, 854

<A NAME="RE06902SS-19A">19a</A> Goosen A. McCleland CW. Rinaldi FC. J. Chem. Soc., Perkin Trans. 2 1993, 279

<A NAME="RE06902SS-19B">19b</A> Goosen A. Marais CF. McCleland CW. Rinaldi FC. J. Chem. Soc., Perkin Trans. 2 1995, 1227

<A NAME="RE06902SS-20A">20a</A> Walling C. Acc. Chem. Res. 1998, 31: 155

<A NAME="RE06902SS-20B">20b</A> Sawyer DT. Sobjowiak A. Matsushita T. Acc. Chem. Res. 1996, 29: 409

<A NAME="RE06902SS-20C">20c</A> MacFaul PA. Wayner DDM. Ingold KU. Acc. Chem. Res. 1998, 31: 159

<A NAME="RE06902SS-21">21</A> Barton DHR. Launay F. Le Gloahec VN. Li T. Smith F. Tetrahedron Lett. 1997, 38: 8491

<A NAME="RE06902SS-22">22</A> MacFaul PA. Arends IWCE. Ingold KU. Wayner DDM. J. Chem. Soc., Perkin Trans. 2 1997, 135

<A NAME="RE06902SS-23">23</A> Kiani S. Tapper A. Staples RJ. Stavropoulos P. J. Am. Chem. Soc. 2000, 122: 7503

<A NAME="RE06902SS-24">24</A> Hartung J. Eur. J. Org. Chem. 2001, 619

<A NAME="RE06902SS-25">25</A> Beckwith ALJ. Hay BP. J. Am. Chem. Soc. 1988, 110: 4415

<A NAME="RE06902SS-26">26</A> Kalvoda J. Heusler K. Synthesis 1971, 501

<A NAME="RE06902SS-27">27</A> Surzur J.-M. Bertrand MP. Bull. Soc. Chim. Fr. 1973, 1861

<A NAME="RE06902SS-28">28</A> Surzur J.-M. In Reactive Intermediates Vol. 2: Abramovitch RA. Plenum Press; New York: 1982. p.121-295

<A NAME="RE06902SS-29">29</A> Brun P. Waegell B. In Reactive Intermediates Vol. 3: Abramovitch RA. Plenum Press; New York: 1983. p.367-426

<A NAME="RE06902SS-30">30</A> Chung TC. Janvikul W. Lu HL. J. Am. Chem. Soc. 1996, 118: 705

<A NAME="RE06902SS-31">31</A> Griller D. Ingold KU. Patterson LK. Scaiano JC. Small RD. J. Am. Chem. Soc. 1979, 101: 3780

<A NAME="RE06902SS-32">32</A> Korth H.-G. Lusztyk J. Ingold KU. J. Org. Chem. 1990, 55: 624

<A NAME="RE06902SS-33A">33a</A> Theodorakis EA. Wilcoxen KM. Chem. Commun. 1996, 1927

<A NAME="RE06902SS-33B">33b</A> Barton DHR. Parekh SI. Half a Century of Free Radical Chemistry Cambridge University Press; Cambridge: 1993.

<A NAME="RE06902SS-34A">34a</A> Newcomb M. Kumar MU. Boivin J. Crépon E. Zard SZ. Tetrahedron Lett. 1991, 32: 45

<A NAME="RE06902SS-34B">34b</A> Newcomb M. Dhanabalasingam B. Tetrahedron Lett. 1994, 35: 5193

<A NAME="RE06902SS-34C">34c</A> Beckwith ALJ. Davison IGE. Tetrahedron Lett. 1991, 32: 49

<A NAME="RE06902SS-35">35</A> Bordwell FG. Zhang S. J. Am. Chem. Soc. 1995, 117: 4858

<A NAME="RE06902SS-36">36</A> Barclay LRC. In Peroxyl Radicals Alfassi Z. Wiley; Chichester: 1997. p.27-48

<A NAME="RE06902SS-37">37</A> Hewgill FR. In MTP International Review of Science Vol. 10: Waters EA. Butterworth; London: 1973. p.167-204

<A NAME="RE06902SS-38">38</A> Hartung J. In Radicals in Organic Synthesis Vol. 2: Renaud P. Sibi MP. Wiley-VCH; Weinheim: 2001. p.425-439

<A NAME="RE06902SS-39A">39a</A> Walling C. Clark RT. J. Am. Chem. Soc. 1974, 96: 4530

<A NAME="RE06902SS-39B">39b</A> Greene FD. Savitz ML. Lau HH. Osterholtz FD. Smith WN. J. Am. Chem. Soc. 1961, 83: 2196

<A NAME="RE06902SS-40">40</A> Ramond TM. Davico GE. Schwartz RL. Lineberger WC. J. Chem. Phys. 2000, 112: 1158

<A NAME="RE06902SS-41">41</A> Endo Y. Saito S. Hirota E. J. Chem. Phys. 1984, 81: 122

<A NAME="RE06902SS-42">42</A> Engelking PC. Ellison BG. Lineberger WC. J. Chem. Phys. 1978, 69: 1826

<A NAME="RE06902SS-43">43</A> Bofill JM. Olivella S. Solé A. Anglada JM. J. Am. Chem. Soc. 1999, 121: 1337

<A NAME="RE06902SS-44">44</A> Saebø S. Radom L. Schaefer HF. J. Chem. Phys. 1983, 78: 845

<A NAME="RE06902SS-45">45</A> Zhu XJ. Ge MF. Wang J. Sun Z. Wang DX. Angew. Chem. Int. Ed. 2000, 39: 1940 ; Angew. Chem. 2000, 112, 2016

<A NAME="RE06902SS-46">46</A> Houle FA. Beauchamp JL. J. Am. Chem. Soc. 1979, 101: 4067

<A NAME="RE06902SS-47">47</A> Wendt HR. Hunziker HE. J. Chem. Phys. 1979, 71: 5202

<A NAME="RE06902SS-48A">48a</A> Avila DV. Lusztyk J. Ingold KU. J. Am. Chem. Soc. 1992, 114: 6576

<A NAME="RE06902SS-48B">48b</A> Avila DV. Ingold KU. Di Nardo AA. Zerbetto F. Zgierski MZ. Lusztyk J. J. Am. Chem. Soc. 1995, 117: 2711

<A NAME="RE06902SS-49">49</A> Iwasaki M. Toriyama K. J. Am. Chem. Soc. 1978, 100: 1964

<A NAME="RE06902SS-50">50</A> Buettner GR. In General Aspects of the Chemistry of Radicals Alfassi Z. Wiley; Chichester: 1999. p.1-18

<A NAME="RE06902SS-51A">51a</A> Kerr JA. In Handbook of Chemistry and Physics 78th Ed.: Lide DR. CRC Press; Boca Raton: 1998. p.951-969

<A NAME="RE06902SS-51B">51b</A> Gregory DD. Jenks WS. J. Org. Chem. 1998, 63: 3859

<A NAME="RE06902SS-52">52</A> Schmidt MW. Truong PN. Gordon MS. J. Am. Chem. Soc. 1987, 109: 5217

<A NAME="RE06902SS-53A">53a</A> Wong SK. Int. J. Chem. Kinet. 1981, 13: 433

<A NAME="RE06902SS-53B">53b</A> Walling C. Kurkov VP. J. Am. Chem. Soc. 1967, 89: 4895

<A NAME="RE06902SS-54">54</A> Howard JA. Scaiano JC. In Kinetische Daten von Radikalreaktionen in Lösung - Oxyl Peroxyl und verwandte Radikale in Landolt-Börnstein Zahlenwerte und Funktionen aus Naturwissenschaft und Technik New Series Part D, Vol. 13: Fischer H. Springer; Berlin: 1984. p.1-127

<A NAME="RE06902SS-55">55</A> Denisov E. In General Aspects of the Chemistry of Radicals Alfassi Z. Wiley; Chichester: 1999. p.79-138

<A NAME="RE06902SS-56">56</A> Walling C. Padwa A. J. Am. Chem. Soc. 1963, 85: 1593

<A NAME="RE06902SS-57A">57a</A> Beckwith ALJ. Hay BP. J. Am. Chem. Soc. 1989, 111: 230

<A NAME="RE06902SS-57B">57b</A> Beckwith ALJ. Hay BP. J. Am. Chem. Soc. 1989, 111: 2674

<A NAME="RE06902SS-58">58</A> Wilsey S. Dowd P. Houk KN. J. Org. Chem. 1999, 64: 8801

<A NAME="RE06902SS-59">59</A> Shubber AK. Dannley RL. J. Org. Chem. 1971, 36: 3784

<A NAME="RE06902SS-60">60</A> Dewar MJS. Kirschner S. J. Am. Chem. Soc. 1971, 93: 4290

<A NAME="RE06902SS-61">61</A> Wentrup C. Reaktive Zwischenstufen I Radikale Carbene Nitrene und gespannte Ringe Thieme; Stuttgart: 1979. p.84-90

<A NAME="RE06902SS-62">62</A> Feray L. Kuznetsow N. Renaud P. In Radicals in Organic Synthesis Vol. 2: Renaud P. Sibi MP. Wiley-VCH; Weinheim: 2001. p.246-278

<A NAME="RE06902SS-63">63</A> Barton DHR. Beaton JM. Geller LE. Pechet MM. J. Am. Chem. Soc. 1961, 83: 4076

<A NAME="RE06902SS-64">64</A> Beckwith ALJ. In MTP International Review of Science Vol. 10: Waters EA. Butterworth; London: 1973. p.3-5

<A NAME="RE06902SS-65">65</A> Ellison DH. Salmon GA. Wilkinson F. Proc. R. Soc. London, Ser. A 1972, 328: 23

<A NAME="RE06902SS-66">66</A> Antonello S. Musumeci M. Wayner DDM. Maran F. J. Am. Chem. Soc. 1997, 119: 9541

<A NAME="RE06902SS-67">67</A> Tupper KJ. Davidson ER. Gajewski JJ. Theor. Chim. Acta 1990, 78: 25

<A NAME="RE06902SS-68A">68a</A> Begley MJ. Fletcher RJ. Murphy JA. Sherburn MS. J. Chem. Soc., Chem. Commun. 1993, 1723

<A NAME="RE06902SS-68B">68b</A> Francisco CG. León EI. Moreno P. Suárez E. Tetrahedron: Asymmetry 1998, 9: 2975

<A NAME="RE06902SS-69">69</A> Beckwith ALJ. Hay BP. Williams GM. J. Chem. Soc., Chem. Commun. 1989, 1202

<A NAME="RE06902SS-70">70</A> Pasto DJ. Cottard F. Tetrahedron Lett. 1994, 35: 4303

<A NAME="RE06902SS-71A">71a</A> Binkley RW. Koholic DJ. J. Org. Chem. 1979, 44: 2047

<A NAME="RE06902SS-71B">71b</A> Honeyman J. Stening TC. J. Chem. Soc. 1958, 537

<A NAME="RE06902SS-72A">72a</A> Sheldon RA. In The Chemistry of Functional Groups Peroxides Vol. 33: Patai S. Wiley; Chichester: 1993. p.161-200

<A NAME="RE06902SS-72B">72b</A> Ingold KU. Acc. Chem. Res. 1969, 2: 1

<A NAME="RE06902SS-72C">72c</A> Hägel E. Kropf H. Margaretha P. Munke S. Pospíil J. Waniczek H. In Houben-Weyl 4th Ed., Vol. E13/1: Kropf H. Thieme; Stuttgart: 1988. p.59-175

<A NAME="RE06902SS-73">73</A> Turner JA. Herz W. J. Org. Chem. 1977, 42: 1900

<A NAME="RE06902SS-74">74</A> Hartung J. Kneuer R. Schwarz M. Svoboda I. Fuess H. Eur. J. Org. Chem. 1999, 97

<A NAME="RE06902SS-75">75</A> Hartung J. Gottwald T. Kneuer R. Synlett 2001, 749

<A NAME="RE06902SS-76">76</A> Hartung J. Hiller M. Schwarz M. Svoboda I. Fuess H. Liebigs Ann. 1996, 2091

<A NAME="RE06902SS-77">77</A> Kim S. Lim CJ. Song S.-E. Kang H.-Y. Synlett 2001, 688

<A NAME="RE06902SS-78">78</A> Kim S. Lee TA. Song Y. Synlett 1998, 471

<A NAME="RE06902SS-79">79</A> Kim S. Lee TA. Synlett 1997, 950

<A NAME="RE06902SS-80A">80a</A> Dulong L. Klein P. Chem. Ber. 1971, 104: 895

<A NAME="RE06902SS-80B">80b</A> Mendenhall GD. Stewart LC. Scaiano JC. J. Am. Chem. Soc. 1982, 104: 5109

<A NAME="RE06902SS-81">81</A> Clerici A. Minisci F. Ogawa K. Surzur J.-M. Tetrahedron Lett. 1978, 1149

<A NAME="RE06902SS-82">82</A> Ho T.-L. In Organic Synthesis by Oxidation with Metal Compounds Mijs WJ. De Jonge CRHI. Plenum Press; New York: 1986. p.569-631

<A NAME="RE06902SS-83A">83a</A> Courtneidge JL. Lusztyk J. Pagé D. Tetrahedron Lett. 1994, 35: 1003

<A NAME="RE06902SS-83B">83b</A> Boto A. Betancor C. Prangé T. Suárez E. J. Org. Chem. 1994, 59: 4393

<A NAME="RE06902SS-83C">83c</A> Concepción JI. Francisco CG. Hernández R. Salazar JA. Suárez E. Tetrahedron Lett. 1984, 25: 1953

<A NAME="RE06902SS-84">84</A> Lee J. Oh J. Jin S.-J. Choi J.-R. Atwood JL. Cha JK. J. Org. Chem. 1994, 59: 6955

<A NAME="RE06902SS-85">85</A> Suginome H. Liu CF. Furosaki A. Chem. Lett. 1985, 27

<A NAME="RE06902SS-86A">86a</A> Barton DHR. Motherwell RSH. Motherwell WB. J. Chem. Soc., Perkin. Trans. 1 1981, 2363

<A NAME="RE06902SS-86B">86b</A> Pasto DJ. Cottard F. Picconatto C. J. Org. Chem. 1994, 59: 7172

<A NAME="RE06902SS-86C">86c</A> Davies AG. Muggleton B. Havari JAA. Tse M.-W. J. Chem. Soc., Perkin Trans. 2 1981, 1132

<A NAME="RE06902SS-87A">87a</A> Krosley KW. Gleicher GJ. J. Phys. Org. Chem. 1993, 6: 228

<A NAME="RE06902SS-87B">87b</A> Krishnamurthy V. Rawal VH. J. Org. Chem. 1997, 62: 1572

<A NAME="RE06902SS-88">88</A> Dowd P. Zhang W. Chem. Rev. 1993, 93: 2091

<A NAME="RE06902SS-89">89</A> Gilbert BC. Marshall PDR. Norman ROC. Pineda N. Williams PS. J. Chem. Soc., Perkin Trans. 2 1981, 1392

<A NAME="RE06902SS-90">90</A> Hoyermann K. Olzmann M. Seeba J. Viskolcz B. J. Phys. Chem. A 1999, 103: 5692

<A NAME="RE06902SS-91">91</A> Baciocchi E. d" Acunzo F. Galli C. Ioele M. J. Chem. Soc., Chem. Commun. 1995, 429

<A NAME="RE06902SS-92">92</A> Kim S. Oh DH. Synlett 1998, 525

<A NAME="RE06902SS-93A">93a</A> Singer LA. Kim SS. Tetrahedron Lett. 1974, 861

<A NAME="RE06902SS-93B">93b</A> Blum PM. Roberts BP. J. Chem. Soc., Perkin Trans. 2 1978, 1313

<A NAME="RE06902SS-94">94</A> Giese B. Radicals in Organic Synthesis: Formation of Carbon-Carbon Bonds Pergamon; Oxford: 1986.

<A NAME="RE06902SS-95">95</A> Breen AP. Murphy JA. Free Rad. Biol. Med. 1995, 18: 1033

<A NAME="RE06902SS-96">96</A> Tezuka T. Narita N. J. Am. Chem. Soc. 1979, 101: 7413

<A NAME="RE06902SS-97">97</A> Jefcoate CRE. Lindsay Smith JR. Norman ROC. J. Chem. Soc. B 1969, 1013

<A NAME="RE06902SS-98">98</A> Boivin J. Crépon E. Zard SZ. Tetrahedron Lett. 1990, 31: 6869

<A NAME="RE06902SS-99">99</A> Adam W. Hartung J. Okamoto H. Saha-Möller CR. pehar K. Photochem. Photobiol. 2000, 72: 619

<A NAME="RE06902SS-100">100</A> Perkin MJ. Radical Chemistry Ellis Horwood; Hertwoodshire: 1994. p.21-32

Adam, W.; Hartung, J.; Okamoto, H.; Marquardt, S.; Nau, W. M.; Pischel, U.; Saha-Möller, C. R.; pehar, K. J. Am. Chem. Soc., submitted.

<A NAME="RE06902SS-102">102</A> Hartung J. Gallou F. J. Org. Chem. 1995, 60: 6706

<A NAME="RE06902SS-103A">103a</A> Newcomb M. Kaplan J. Tetrahedron Lett. 1987, 28: 1615

<A NAME="RE06902SS-103B">103b</A> Newcomb M. Park SU. J. Am. Chem. Soc. 1986, 108: 4132

<A NAME="RE06902SS-104">104</A> Hartung J. Giese B. Chem. Ber. 1992, 125: 1777

<A NAME="RE06902SS-105">105</A> Chatgilialoglou C. In Radicals in Organic Synthesis Vol. 1: Renaud P. Sibi MP. Wiley-VCH; Weinheim: 2001. p.28-49

<A NAME="RE06902SS-106">106</A> Hartung J. Hertel B. Trach F. Chem. Ber. 1993, 126: 1187

<A NAME="RE06902SS-107">107</A> Surzur J.-M. Bertrand M.-P. Nougier R. Tetrahedron Lett. 1969, 4197

<A NAME="RE06902SS-108">108</A> Hartung J. Stowasser R. Vitt D. Bringmann G. Angew. Chem., Int. Ed. Engl. 1996, 35: 2820 ; Angew. Chem. 1996, 108, 3056

<A NAME="RE06902SS-109">109</A> Hartung J. Hiller M. Schmidt P. Liebigs Ann. 1996, 1425

Hartung, J.; Kneuer, R.; Schmidt, P.; pehar, K.; Svoboda, I.; Fuess, H. Eur. J. Org. Chem., manuscript in preparation.

<A NAME="RE06902SS-111">111</A> Hartung J. Kopf TM. Kneuer R. Schmidt P. C. R. Acad. Sci. Paris Chemie/Chemistry 2001, 649

<A NAME="RE06902SS-112">112</A> Beckwith ALJ. Schiesser CH. Tetrahedron 1985, 41: 3925

<A NAME="RE06902SS-113">113</A> Spellmeyer DC. Houk KN. J. Org. Chem. 1987, 52: 959

<A NAME="RE06902SS-114">114</A> Guindon Y. Denis RC. Tetrahedron Lett. 1998, 39: 339

<A NAME="RE06902SS-115">115</A> Hartung J. Kneuer R. pehar K. Chem. Commun. 2001, 799

<A NAME="RE06902SS-116">116</A> Hartung J. Kneuer R. Eur. J. Org. Chem. 2000, 1677

<A NAME="RE06902SS-117">117</A> Eugster CH. Naturwissenschaften 1968, 55: 305

<A NAME="RE06902SS-118">118</A> Wang P.-C. Joullié MM. The Alkaloids 1984, 23: 327

Hartung,. J.; Schmidt, P. Synlett, manuscript in preparation.

<A NAME="RE06902SS-120">120</A> Hartung J. Hiller M. Schmidt P. Chem.-Eur. J. 1996, 2: 1014

<A NAME="RE06902SS-121">121</A> Togo H. Muraki T. Hoshina Y. Yamaguchi K. Yokoyama M. J. Chem. Soc., Perkin Trans. 1 1997, 787

<A NAME="RE06902SS-122">122</A> Gadwood RC. Kamdar BV. Dubray LAC. Wolfe ML. Smith MP. Watt W. Mizsak SA. Groppi VE. J. Med. Chem. 1993, 36: 1480

<A NAME="RE06902SS-123">123</A> Johns A. Murphy JA. Tetrahedron Lett. 1988, 29: 837

<A NAME="RE06902SS-124">124</A> Kim S. Kim KH. Cho JR. Tetrahedron Lett. 1997, 38: 3915

<A NAME="RE06902SS-125">125</A> Bertrand MP. Surzur JM. Boyer M. Mihailovic MLj. Tetrahedron 1979, 35: 1365

<A NAME="RE06902SS-126">126</A> Orito K. Ohto M. Suginome H. J. Chem. Soc., Chem. Commun. 1990, 1076

<A NAME="RE06902SS-127">127</A> Saito I. Nittala SS. In The Chemistry of Functional Groups Peroxides Patai S. Wiley; Chichester: 1983. p.311-374

Hartung, J.; Kneuer, R.; Rummey, C.; Bringmann, G. J. Am. Chem. Soc., manuscript in preparation.

Geometrical data which are mentioned in the text were obtained from an UB3LYP/6-31+G**//UB3LYP/6-31+G**-optimized transition structure 84 For comparison with data obtained from earlier UHF calculations (see. ref. [109] ), transition structure 84 was in addition optimized using UHF/6-31+G**//UHF/6-31+G**-calculations: E = -231361265 Hartree 〈S ²〉 = 1.003; i = -689 cm^-1; transition structure geometry: d_C1-O = 1.903 Å, α_O-C1-C2 = 108.07°; sum of Mulliken charges: methoxyl radical substructure: -0.12, propene moiety:+0.12

<A NAME="RE06902SS-130A">130a</A> Foresman B. Frisch . Exploring Chemistry with Electronic Structure Methods 2nd Ed.: Gaussian Inc; Pittsburgh: 1996.

<A NAME="RE06902SS-130B">130b</A> Jensen F. Introduction to Computational, Chemistry Wiley; Chichester: 1999.

<A NAME="RE06902SS-131">131</A> Wong PC. Griller D. Scaiano JC. J. Am. Chem. Soc. 1982, 104: 5106

<A NAME="RE06902SS-132">132</A> Jones MJ. Moad G. Rizzardo E. Solomon DH. J. Org. Chem. 1989, 54: 1607

<A NAME="RE06902SS-133">133</A> Atkinson R. J. Phys. Chem. Ref. Data 1997, 26: 215

<A NAME="RE06902SS-134">134</A> Alvarez-Idaboy JR. Mora-Diez N. Vivier-Bunge A. J. Am. Chem. Soc. 2000, 122: 3715

<A NAME="RE06902SS-135A">135a</A> Barckholtz C. Barckholtz TA. Hadad CM. J. Phys. Chem. A 2001, 105: 140

<A NAME="RE06902SS-135B">135b</A> García-Cruz I. Castro M. Vivier-Bunge A. J. Comput. Chem. 2000, 21: 716

<A NAME="RE06902SS-136">136</A> Ricca A. Bauschlicher CW. Chem. Phys. Lett. 2000, 328: 396

<A NAME="RE06902SS-137">137</A> Lundqvist MJ. Eriksson LA. J. Phys. Chem. B 2000, 104: 848

<A NAME="RE06902SS-138">138</A> Urano Y. Higuchi T. Hirobe M. Nagano T. J. Am. Chem. Soc. 1997, 119: 12008

<A NAME="RE06902SS-139">139</A> Fleming I. Grenzorbital und Reaktionen organischer Verbindungen Wiley-VCH; Weinheim: 1990.

<A NAME="RE06902SS-140">140</A> Steenken S. Chem. Rev. 1989, 89: 503

<A NAME="RE06902SS-141">141</A> Finkelstein E. Rosen GM. Rauckman EJ. J. Am. Chem. Soc. 1980, 102: 4994

<A NAME="RE06902SS-142">142</A> Dikalov SI. Mason RP. Free Radical Biol. Med. 2001, 30: 187

<A NAME="RE06902SS-143">143</A> Suárez E. Rodriguez MS. In Radicals in Organic Synthesis Vol. 2: Renaud P. Sibi MP. Wiley-VCH; Weinheim: 2001. p.440-454

<A NAME="RE06902SS-144A">144a</A> Griller D. Ingold KU. Acc. Chem. Res. 1980, 13: 317

<A NAME="RE06902SS-144B">144b</A> Newcomb M. In Radicals in Organic Synthesis Vol. 1: Renaud P. Sibi MP. Wiley-VCH; Weinheim: 2001. p.317-336

<A NAME="RE06902SS-145A">145a</A> Batt L. Hisham MWM. Mackay M. Int. J. Chem. Kinet. 1989, 21: 535

<A NAME="RE06902SS-145B">145b</A> Fittschen C. Hippler H. Viskolcz B. Phys. Chem. Chem. Phys. 2000, 2: 1677

<A NAME="RE06902SS-146A">146a</A> Kaptein R. Brokken-Zijp J. de Kanter FJJ. J. Am. Chem. Soc. 1972, 94: 6280

<A NAME="RE06902SS-146B">146b</A> Braun W. Rajbenbach L. Eirich FR. J. Phys. Chem. 1962, 66: 1591

<A NAME="RE06902SS-147">147</A> Avila DV. Brown CE. Ingold KU. Lusztyk J. J. Am. Chem. Soc. 1993, 115: 466

<A NAME="RE06902SS-148">148</A> Zhang W. In Radicals in Organic Synthesis Vol. 2: Renaud P. Sibi MP. Wiley-VCH; Weinheim: 2001. p.234-245

<A NAME="RE06902SS-149">149</A> Mehta G. Krishnamurthy N. Karra SR. J. Am. Chem. Soc. 1991, 113: 5765

<A NAME="RE06902SS-150">150</A> Benati L. Nanni D. Sangiorgi C. Spagnolo P. J. Org. Chem. 1999, 64: 7836

<A NAME="RE06902SS-151">151</A> Suginome H. Liu CF. Tokuda M. J. Chem. Soc., Chem. Commun. 1984, 334

<A NAME="RE06902SS-152">152</A> de Armas P. García-Tellado F. Marrero-Tellado JJ. Robbles J. Tetrahedron Lett. 1997, 38: 8081

<A NAME="RE06902SS-153">153</A> Francisco CG. Freire R. González CC. León EI. Riesco-Fagundo C. Suárez E. J. Org. Chem. 2001, 66: 1861

<A NAME="RE06902SS-154">154</A> González CC. Kennedy AR. León EI. Riesco-Fagundo C. Suárez E. Angew. Chem. Int. Ed. 2001, 40: 2326 ; Angew. Chem. 2001, 113, 2388

<A NAME="RE06902SS-155">155</A> Tsang R. Fraser-Reid B. J. Am. Chem. Soc. 1986, 108: 8102

<A NAME="RE06902SS-156">156</A> Martín A. Rodríguez MS. Suárez E. Tetrahedron Lett. 1999, 40: 7525

<A NAME="RE06902SS-157">157</A> Francisco CG. Martín A. C G. Suárez E. J. Org. Chem. 1998, 63: 2099

<A NAME="RE06902SS-158">158</A> Hernández R. León EI. Moreno P. Suárez E. J. Org. Chem. 1997, 62: 8974

<A NAME="RE06902SS-159">159</A> Nishida A. Takahashi H. Takeda H. Takada N. Yonemitsu O. J. Am. Chem. Soc. 1990, 112: 902

<A NAME="RE06902SS-160A">160a</A> Peeters J. Vereecken L. Fantechi G. Phys. Chem. Chem. Phys. 2001, 3: 5489

<A NAME="RE06902SS-160B">160b</A> Dibble TS. J. Am. Chem. Soc. 2001, 123: 4228

<A NAME="RE06902SS-161">161</A> Pryor B. Porter NA. Free Rad. Biol. Med. 1990, 8: 541

<A NAME="RE06902SS-162A">162a</A> Gardner HW. Free Rad. Biol. Med. 1989, 7: 65

<A NAME="RE06902SS-162B">162b</A> Esterbauer H. Schaur RJ. Zollner H. Free Rad. Biol. Med. 1991, 11: 81

<A NAME="RE06902SS-163">163</A> Banks JT. Scaiano JC. J. Phys. Chem. 1995, 99: 3527

<A NAME="RE06902SS-164">164</A> Falvey DE. Khambatta BS. Schuster GB. J. Phys. Chem. 1990, 94: 1056

<A NAME="RE06902SS-165">165</A> Grossi L. Strazzari S. J. Org. Chem. 2000, 65: 2748

<A NAME="RE06902SS-166">166</A> Brook AG. Acc. Chem. Res. 1974, 7: 77

<A NAME="RE06902SS-167">167</A> Paredes MD. Alonso R. J. Org. Chem. 2000, 65: 2292

<A NAME="RE06902SS-168">168</A> Tsai Y.-M. Cherng C.-D. Tetrahedron Lett. 1991, 32: 3515

<A NAME="RE06902SS-169">169</A> Chang S.-Y. Jiaang W.-T. Cherng C.-D. Tang K.-H. Huang C.-H. Tsai Y.-M. J. Org. Chem. 1997, 62: 9089

<A NAME="RE06902SS-170">170</A> Schiesser CH. Styles ML. J. Chem. Soc., Perkin Trans. 2 1997, 2335

<A NAME="RE06902SS-171">171</A> Curran DP. Liu H. J. Org. Chem. 1991, 56: 3463

<A NAME="RE06902SS-172">172</A> Rothenberg G. Sasson Y. Tetrahedron 1998, 54: 5417

<A NAME="RE06902SS-173">173</A> Sakurai H. Hosomi A. J. Am. Chem. Soc. 1967, 89: 458

<A NAME="RE06902SS-174A">174a</A> Walling C. Jacknow BB. J. Am. Chem. Soc. 1960, 82: 6113

<A NAME="RE06902SS-174B">174b</A> Bennett JE. Gilbert BC. Lawrence S. Whitwood AC. Holmes AJ. J. Chem. Soc., Perkin Trans. 2 1996, 1789

<A NAME="RE06902SS-175A">175a</A> Malatesta V. Ingold KU. J. Am. Chem. Soc. 1981, 103: 609

<A NAME="RE06902SS-175B">175b</A> Beckwith ALJ. Easton C. J. Am. Chem. Soc. 1981, 103: 615

<A NAME="RE06902SS-176">176</A> Maul JJ. Ostrowski PJ. Ublacker GA. Linclau B. Curran DP. Top. Curr. Chem. 1999, 206: 79

<A NAME="RE06902SS-177A">177a</A> Li B. Gutierrez PL. Blough NV. Anal. Chem. 1997, 69: 4295

<A NAME="RE06902SS-177B">177b</A> Babbs CF. Griffin DW. Free Radical Biol. Med. 1989, 6: 493

<A NAME="RE06902SS-178">178</A> Hornung G. Schalley CA. Dieterle M. Schröder D. Schwarz H. Chem.-Eur. J. 1997, 3: 1866

<A NAME="RE06902SS-179">179</A> Freidlina RKH. Terent’ev AB. In Advances in Free-Radical Chemistry Vol. 6: Williams GH. Heyden; London: 1980. p.1-63

<A NAME="RE06902SS-180">180</A> Viskolcz B. Lendvay G. Körtvélyesi T. Seres L. J. Am. Chem. Soc. 1996, 118: 3006

<A NAME="RE06902SS-181">181</A> Majetich G. Wheless K. Tetrahedron 1995, 51: 7095

Hartung, J., unpublished results. The photoreaction of thione 162 [74] in benzene was performed as described in ref. [120] R _f 02 (petroleum ether-EtOAc, 3:1); ¹H NMR (CDCl₃) δ = 1.38 (d, J = 7.0 Hz, 3 H), 1.65-1.80 (m, 3 H), 1.80-2.01 (m, 1 H), 2.52 (br s, 1 H), 3.71 (m_c, 1 H), 3.94 (m_c, 1 H), 6.96 (ddd, J = 0.9, 4.9, 7.3 Hz, 1 H), 7.16 (dt, J = 0.91, 8.2, 1 Hz), 7.46 (ddd, J = 1.8, 7.3, 8.1 Hz, 1 H), 8.38 (ddd J = 0.9, 1.8, 4.9 Hz, 1 H). ¹³C NMR (CDCl₃): δ = 20.5, 29.6, 33.9, 62.3, 77.3, 119.6, 123.2, 136.0, 149.5, 159.7 Anal. Calcd for C₁₀H₁₅NOS: C, 60.88; H, 7.66, N, 7.10; S, 16.25. Found: C, 60.48; H, 7.30, N, 7.28; S, 16.66

<A NAME="RE06902SS-183A">183a</A> Dorigo AE. Houk KN. J. Am. Chem. Soc. 1987, 109: 2195

<A NAME="RE06902SS-183B">183b</A> Dorigo AE. McCarrick MA. Loncharich RJ. Houk KN. J. Am. Chem. Soc. 1990, 112: 7508

<A NAME="RE06902SS-184">184</A> Bergmark WR. Beckmann B. Lindenberger W. Tetrahedron Lett. 1971, 2259

<A NAME="RE06902SS-185">185</A> Hernández R. Velázquez SM. Suárez E. Rodríguez MS. J. Org. Chem. 1994, 59: 6395

<A NAME="RE06902SS-186">186</A> Crich D. Huang X. Newcomb M. J. Org. Chem. 2000, 65: 523

<A NAME="RE06902SS-187A">187a</A> Dorta RL. Martín A. Salazar JA. Suárez E. Prangé T. J. Org. Chem. 1998, 63: 2251

<A NAME="RE06902SS-187B">187b</A> Martín A. Salazar JA. Suárez ET. J. Org. Chem. 1996, 61: 3999

<A NAME="RE06902SS-188">188</A> Dorta RL. Martín A. Salazar JA. Suárez E. Tetrahedron Lett. 1996, 37: 6021

<A NAME="RE06902SS-189">189</A> Orito K. Sato S. Suginome H. J. Chem. Soc., Perkin Trans. 1 1995, 63

<A NAME="RE06902SS-190">190</A> Adam W. Grimm GN. Saha-Möller CR. Free Radical Biol. Med. 1998, 24: 234

<A NAME="RE06902SS-191">191</A> Adam W. Grimm GN. Saha-Möller CR. Dall’Acqua F. Miolo G. Vedaldi D. Chem. Res. Toxicol. 1998, 11: 1089

<A NAME="RE06902SS-192">192</A> Pogozelski WK. Tullius TD. Chem. Rev. 1998, 98: 1089

<A NAME="RE06902SS-193">193</A> Pardo L. Banfelder JT. Osman R. J. Am. Chem. Soc. 1992, 114: 2382

<A NAME="RE06902SS-194">194</A> Giese B. Burger J. Kang TW. Kesselheim C. Wittmer T. J. Am. Chem. Soc. 1992, 114: 7322