Journal of Photoscience

Korean Society of Photoscience (한국광과학회)
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Recent Advances in Di-$\pi$-methane Processes. Novel Reactions of 1,4-Unsaturated Compounds Promoted by Triplet Sensitization and Photoelectron Transfer

  • Armesto, Diego (Departamento de Quimica Organica Facultad de Ciencias Quimicas Universidad Complutense) ;
  • Ortiz, Maria J. (Departamento de Quimica Organica Facultad de Ciencias Quimicas Universidad Complutense) ;
  • Agarrabeitia, Antonia R. (Departamento de Quimica Organica Facultad de Ciencias Quimicas Universidad Complutense)
  • Published : 2003.04.01
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Abstract

Recent studies on the photoreactivity of l,4-unsaturated systems have changed some ideas that were firmly established in this area of research for many years. Thus, we have described the first examples of 2-aza-di-$\pi$-methane (2-ADPM) rearrangements promoted by triplet-sensitization and by single electron transfer (SET) using electron-acceptor sensitizers. These reactions afford N-vinylaziridine and cyclopropylimine photoproducts in the first examples of di-$\pi$-methane processes that yield three-membered ring heterocycles. l-Aza-1,4-dienes also undergo SET-promoted l-aza-di-$\pi$-methane (l-ADPM) rearrangements via radical-cation intermediates using electron acceptor sensitizers. In some cases, alternative cyclizations yielding different carbocycles and heterocycles have been observed. The l-ADPM and di-$\pi$-methane (DPM) reactions also occur via radical-anion intermediates on irradiation using electron donor sensitizers. On the other hand, the photoreactivity reported for $\beta$,${\gamma}$-unsaturated aldehydes for many years was decarbonylation to the corresponding alkenes. However, our studies demonstrate that these compounds undergo the oxa-di-$\pi$-methane (ODPM) rearrangement with high chemical and quantum efficiency. A comparison of the photochemical reactivity of $\beta$,${\gamma}$-unsaturated aldehydes and corresponding methyl ketones has shown that the ketones do not undergo the ODPM rearrangement while the corresponding aldehydes are reactive by this pathway. Monosubstituted $\beta$,${\gamma}$-unsaturated aldehydes at C-2 undergo the ODPM rearrangement yielding the corresponding cyclopropane carbaldehydes diastereoselectively. Finally, we have described the first examples of reactions, similar to the well know Norrish Type I process, which take place in the triplet excited state of $\beta$,${\gamma}$-unsaturated carbonyl compounds by excitation of the C-C double bond instead of the carbonyl group.

Keywords

References

  1. Chem. Rev. v.96 Synthetic aspects of the di-π-methane rearrangement Zimmerman,H.E.;D.Armesto
  2. Organic Photochemistry v.11 The di-π-methane rearrangement Zimmerman,H.E.;Padwa,A(ed.)
  3. Top. Curr. Chem. v.54 Photochemistry of β,γ-unsaturated ketones Dauben,G.W.;G.Lodder;J.Ipaktschi
  4. Chem. Rev. v.76 The photochemistry and spectroscopy of β,γ-unsaturated carbonyl compounds Houk,K.N.
  5. Rearrangements in Ground and Excited States v.3 Photochemical rearrangements of β,γ-enones Schuster,D.I.;DeMayo,P.(ed.)
  6. Organic Photochemistry v.11 The Oxadi-π-methane rearrangement Demuth,M.;Padwa,A.(ed.)
  7. CRC Handbook of Organic Photochemistry and Photobiology The Azadi-π-methane rearrangement Armesto,D.;Horspool,W.M.(ed.);Soon,P.S.(ed.)
  8. EPA Newsletter v.53 Influence of nitrogen incorporation on the photoreactivity of some unsaturated systems Armesto,D.
  9. J. Am. Chem. Soc. v.119 Novel photorearrangements of 2-aza-1,4-dienes to produce vinylaziridines and cyclopropylimines Armesto,D.;O.Caballero;U.Amador
  10. J. Org. Chem. v.61 Novel Radical Cation Reactions of Bichromophoric Systems. Transannular Aryl Migrations; Mechanistic and Exploratory Organic Photochemistry Zimmerman,H.E.;K.D.Hoffacker
  11. Tetrahedron Lett. v.40 The novel 1-aza-di-π-methane rearrangement of 1-substituted-1-aza-1,4-dienes promoted by DCA-sensitization Ortiz,M.J.;A.R.Agarrabeitia;S.Aparicio-Lara;D.Armesto
  12. J. Org. Chem. v.67 Photochemical reactivity of 1-substituted-1-aza-1,4-dienes promoted by electron-acceptor sensitizers. Di-π-methane rearrangements and aleternative reactions via radical-cation intermediates Armesto,D.;M.J.Ortiz;A.R.Agarrabeitia;S.Aparicio-Lara;M.Martin-Fontecha;M.Liras;M.P.Martinez-Alcazar
  13. J. Am. Chem. Soc. v.113 Use of sterically hindered sensitizers for improved photoinduced electron-transfer reactions Gassman,P.G.;S. A. De Silva
  14. J. Am. Chem. Soc. v.123 Di-π-methane reactions promoted by SET from electron-donor sensitizers Armesto,D.;M.J.Ortiz;A.R.Agarrabeitia;M.Martin-Fontecha
  15. Chem. Rev. v.86 Photosensitization by reversible electron transfer: theories, experimental evidence, and examples Kavarnos,G.J.;N.J.Turro
  16. Tetrahedron Lett. v.23 A novel aza-di-π-methane rearrangement. The photoreaction of 4,4-dimethyl-1,6,6-triphenyl-2-azahexa-2,5-diene Armesto,D.;J.F.Martin;R.Perez-Ossorio;W.M.Horspool
  17. J. Am. Chem. Soc. v.101 Unusual Organic Photochemistry Effected by Cyano and Methoxy Substitution. Exploratory and Mechanistic Organic Photochemistry Zimmerman,H.E.;D.Armesto;M.G.Amezua;T.P.Gannett;P.Johnson
  18. J. Am. Chem. Soc. v.92 Unsymmetrical substitution and the direction of the di-π-methane rearrangement. Mechanistic and exploratory organic photo-chemistry. LVI Pratt,A.C.;H.E.Zimmerman
  19. Helv. Chim. Acta. v.51 Zur photochemie von α,β-ungesattigten γ-aldehydoketonen I. Die UV.-bestrahlung von 3,19-dioxo-17β-acetoxy-△$^4$-andostren Pfenninger,E.;D.E.Poel;C.Berse;H.Wehrli;K.Schaffner;O.Jeger
  20. J. Org. Chem. v.54 Unusual rearrangements in di-π-methane systems: Mechanistic and exploratory organic photochemistry Zimmerman,H.E.;J.M.Cassel
  21. J. Org. Chem. v.61 Unexpected oxadi-π-methane rearrangement of β,γ-unsaturated aldehydes Armesto,D.;M.J.Ortiz;S.Romano;A.R.Agarrabeitia;M.G.Gallego;A.Ramos
  22. Synthesis Diastereoselective synthesis of cyclopropanecar-baldehydes Armesto,D.;M.J.Ortiz;A.R.Agarrabeitia;S.Aparicio-Lara
  23. Recl. Trav. Chim. Pays-Bas v.96 Photochemistry of β,γ-unsaturated ketones. The effect of substituents at the α-C and the carbonyl group on the occurrence of the oxa-di-π-methane rearrangement van der Weerdt, A. J. A.;H.Cerfontain
  24. J. Am. Chem. Soc. v.88 Novel Photocyclization of a highly phenylated β,γ-unsaturated ketone to a cyclopropyl ketone, involving benzoyl group migration Tenney,L.P.;D.W.Boykin,Jr.;R.E.Lutz