STEREOCHEMISTRY IN LONG-CHAIN BIRADICAL CYCLIZATION

  • 발행 : 1997.03.01

초록

The structures of 8-membered azalactone isomers produced from photocyclization of 2-(N,N-dibenzylamino)ethyl benzoylacetate were determined by the X-ray structure analysis to clarify the stereochemical behavior of a 1,8-biradical. The remarkable stereoselectivity in cyclization of the 1,8-biradical to form cis- and trans-isomers of the azalactone was not observed. The ring conformations were boat-chair like and dihedral angles between C$_5$- and C$_6$- phenyl groups were ca 45$\circ$ in the both isomers. The 1,8-biradicals in the transition state for the cyclization would have nearly same boat-chair like conformation and twisted configuration with the dihedral angle of ca 45$\circ$ as the corresponding isomer, and this is responsible for luck of stereoselectivity in long-chain biradical cyclization.

키워드

참고문헌

  1. Acc. Chem. Res. v.4 Type II photoelimination and photocyclization of ketones Wagner, P.J.
  2. Acc. Chem. Res. v.16 Conformational flexibility and photochemistry Wagner, P.J.
  3. Rearrangements in Ground and Excited States v.Essay 20 Photorearrangements via biradicals of simple carbonyl compounds Wagner, P. J.;Mayo P.(ed.)
  4. Organic Photochemistry v.11 Photoinduced hydrogen atom abstraction by carbonyl compounds Wagner, P. J.;B. -S. Park;Padwa, A.(ed.)
  5. J. Am. Chem. Soc. v.90 Stereoelectronic requirements for the type II cleavage of cis-and trans-4-t-butylcyclohexanones Turro, N. J.;D. S. Weiss
  6. J. Org. Chem. v.53 Synthesis and photochemistry of some new pentacy-cloundecan-8-ones. Probes for hydrogen adstraction in the π-plane Sauers, R. R.;A. Scimone;H. Shams
  7. J. Am. Chem. Soc. v.94 Type II photoprocesses of pheny1 ketones. Competitive δ-hydrogen abstration and the geometry of intramolecular hydrogen atom transfers Wagner, P. J.;P. A. Kelso;A. E. Kemppaonen;R. G. Zepp
  8. Acc. Chem. Res. v.22 1,5-Biradicals and five-membered rings generates by δ-hydrogen abstraction in photoexcited ketones Wagner, P. J.
  9. Tetrahedron Lett. v.25 Photochemical ε-hydrogen abstraction as a route to tetrahydropyran-3-ols Carless, H. A. J.;G. K. Fekarurhobo
  10. J. Org. Chem. v.50 Photoclization of α-[0-(benzyloxy)pheny1]acetophenone : Triplet-state ε-hydrogen abstraction Meador, M. A.;P. J. Wagner
  11. J. Am. Chem. Soc. v.96 Conformational analysis of hydrocarbon chains in solution. Carbon tetracholride Winnik, M. A.;C. K. Lee;S. Basu;D. S. Saunder
  12. Acc. Chem. Res. v.10 Photochemical probes of hydrocarbon chain conformation in solustion Winnik, M. A.
  13. Chem. Rev. v.81 Cyclization and the conformation of hydrocarbon chains Winnik, M. A.
  14. Acc. Chem. Res. v.13 Biomimetic control of chemical selectivity Breslow, R.
  15. J. Chem. Soc. Chem. Commun. Remote photocyclization of (diben-zylamino)ethyl benzoylacetate. Intermolecular hydrogen abstraction through a ten-membered cyclic transition state Hasegawa, T.;K. Miyata;T. Ogawa;N. Yoshihara;M. Yoshioka
  16. J. Chem. Soc. Perkin Trans. v.1 Photoeyelization of co-(dialkylamino)alkyl β-oxoesters via remote hydrogen transfer Hasegawa,T.;T. Ogawa;K. Miyata;A. Karakizawa;M. Komiyama;K. Nishizawa;M. Yoshioka
  17. J. Chem. Soc. Chem. Commun. Intramolecular hydrogen abstraction in ketone photochemistry : The first examples of ζ-hydrogen abstraction Carless, H. A. J.;S. M.-Kibenda
  18. Bull. Chem. Soc. Jpn. v.63 Photoreactions of 2-(dialkyamino)ethyl esters of γ-oxo acids via remote hydrogen transfer : Influence of the stability and confromational flexibility of the biradical intermediate on its chemical behavior Hasegawa, T.;K. Mukai;K. Mizukoshi;M. Yoshioka
  19. Bull. Chem. Soc. Jpn. v.66 Novel biradical cyclization via remotehydrogen transfer in photochemistry of 2-dialkyl-aminoethyl 3-benzoyacrylates Hasegawa, T.;Y. Yamazaki;M. Yochioka
  20. J. Chem. Soc. Chem. Commun. Photocyclization of β-oxesters : Limiting factors for remote hydrogen abstraction through a medium-sized cyclic transition state Hasegawa, T.;Y. Horikoshi;S. Iwata;M. Yahioka
  21. Bull. Chem. Soc. Jpn. v.65 Photochemical reactions of 4-oxo carboxylic esters : Remote hydrogen abstraction and eistrans isomerization Hasegawa, T.;K. Takashima;H. Aoyama;M. Yoshioka
  22. J. Am. Chem. Soc. v.114 1.5-and 1.9-hydrogen atom abstractions. Photochemical strategies for radical cyclization Kraus, G. A.;Y. Wu
  23. J. Phys. Org. Chem. v.9 Photocyclization of 2-(dialiylamino)ethyl acetoactates : Remote proton transfer and Stern-Volmer quenching kineties in the system involving two reactive excited states Haesgawa, T.;N. Tasuda;M. Yoshioka
  24. J. Am. Chem. Soc. v.92 Photochemistry of methyl-substituted butyrophenones. The nature of the 1,4-biradical interrnediates Lewis, F. D.;T. A. Hilliard
  25. J. Chem. Ed. v.62 A simple method to perform a liquid diffusion crystallization Orvig, C.
  26. J. Appl. Cryst. v.17 MITHRIL-An integrated direct methods computer program Gilmore, C. J.
  27. Technical Report 1984 Direct methods for difference structures-An automatic procedure for phase extension and refinement of difference estructrue factors Beurskens, P. T.
  28. International Tables for X-ray Crystallography v.IV Kluwer Academic Puplishers
  29. Acta Crystallogr. v.17 Dispersion corrections and crystal structure refinements Ibers, J. A.;W. C. Hamilton
  30. International Tables for X-ray Crystallography v.IV Kluwer Academic Publishers
  31. TEXSAN-TEXRAY Structure Analysis Package Molecular Strucature Corporation
  32. Chem. Rev. v.73 Photoreduction by amines Cohen, S. G.;A. Parola;G. H. Parsons. Jr.
  33. Chem. Rev. v.86 Photosensitizations by reversible electron transfer : Theories, experimental evidence and examples Kavarnos, G. J.;N. J. Turro
  34. J. Am. Chem. Soc. v.89 Molecular geometry. V. Evaluation of functions and conformations of medium rings Hendrickson, J. B.
  35. J. Am. Chem. Soc. v.77 Cyclic aminoacyloins and aminoketones, IV. Dependence of transnnular interaction upon the relative location of N and $C_{CO}$ Leonard, N. J.;M. Oki;S. Chiavarelli
  36. J. Am. Chem. Soc. v.77 Cyclic aminoacyloins and aminoketones. V. Detailed infarared spectral study of transnnular interaction between N and $C_{CO}$ Leonard, N. J.;M. Oki;J. Brader;H. Boaz