1. Anion radical coupling

2. Plan  methods for the formation of aryl-aryl bonds  anionic cyclohydrogenation  history  mechanism  applications

3. Selective formation of aryl-aryl bonds between reaction partners (no functionality other than C-H bonds at the carbon atom):  transition metal catalyzed cross-coupling reactions  oxidative dimerization of electron-rich arenes (Scholl, Kovacic and others)  intramolecular oxidative dimerization (Müllen)  oxidative photocyclization of stilbenes to phenanthrenes (Mallory reaction)  thermal cyclodehydrogenations by flash vacuum pyrolysis  anionic cyclodehydrogenation of aromatic hydrocarbons

4. Classic example of anionic cyclodehydrogenation: Oxidative cyclization of 1,10-binaphthyl (1) to perylene (2 ) M. Rickhaus, A.P. Belanger, H. A. Wegner, L.T. Scott, J.Org.Chem. 2010, 75, 7358

5. Anion radical coupling as an unique method  the highest efficiency in conversion 1,1’-binaphthyl to perylene  alkali metals are used to induce oxidation

6. Classic example of anionic cyclodehydrogenation: Oxidative cyclization of 1,10-binaphthyl (1) to perylene (2 ) M. Rickhaus, A.P. Belanger, H. A. Wegner, L.T. Scott, J.Org.Chem. 2010, 75, 7358

7. History first isolated by Miller mechanism discovered by accident in 1967 by Solodovnikov et al. H.Gilman, C.G.Brennen, J. Am. Chem. Soc. 1949, 71, 657 M. Rickhaus, A.P. Belanger, H. A. Wegner, L.T. Scott, J.Org.Chem. 2010, 75, 7358

8. Definition Aromatic radical anion Ar + e - → Ar ●- Ar ●- + e - → Ar 2- N. L. Holy, Chem. Rev. 1974, 74, 243

9. General types of anion reactions

11. Reactivity of a radical anion Compound Electron affinity [eV] Naphthalene Triphenylene Phenantrhrene Anthracene 0,152 ± 0,016 0,284 ± 0,020 0,308 ± 0,024 0,552 ± 0,061 N. L. Holy, Chem. Rev. 1974, 74, 243

12. Mechanism M. Rickhaus, A.P. Belanger, H. A. Wegner, L.T. Scott, J.Org.Chem. 2010, 75, 7358 The equilibrium constatnt depends on:  nature of the metal  hydrocarbon  solvent  temperature M + Ar → Ar ●- + M +

13. M. Rickhaus, A.P. Belanger, H. A. Wegner, L.T. Scott, J.Org.Chem. 2010, 75, 7358

18. Examined conditions K (in an excess), THF, at 80 º C gave 73% yield Other conditions examined (metal, solvent, temperature) gave yelds of 10% or less: a) K, 1,2-dimethoxyethane, 80 º C b) K, diglyme, 80 º C c) K, toluene, 80 º C d) Na, THF, 66 º C e) Na, diglyme, 80 º C f) Na, TMEDA, 120 º C g) Na, toluene, 110 º C M. Rickhaus, A.P. Belanger, H. A. Wegner, L.T. Scott, J.Org.Chem. 2010, 75, 7358

19. Oxidative agent  exposure to oxygene (small scale)  elemental iodine  Na 2 S 2 O 5  SO 2 S.H.Bossmann, H.Durr, M.R. Pokhrel, Synthesis 2005, 6, 907

20. SO 2 as an oxidative agent S. Hunig, I. Wehner, Synthesis 1989, 552

21. Applications P. Schlichting, U. Rohr, K. Müllen, J. Mater. Chem. 1998, 8, 2651

22. Applications

23. Reductive ring closure of helicenes A. Ayalon, M. Rabinovitz, Tetrahedron Lett. 1992, 33, 17, 2395

24. Applications Terrylene synthesis U.Scherf, K. Müllen, Synthesis 1992, 23

25. Summary formation of aryl-aryl bonds efficiency unique method oxidazing agent obscure mechanism

26. Thank you !!! Questions ???