Synthesis of expanded planar dehydrobenzoannulenes: Weakly diatropic, weakly paratropic, or atropic?

Tetrahedron Letters

Volumn 39, Issue 38, 1998, Pages 6795-6798

  Wan, W Brad ^a   Kimball, David B ^a   Haley, Michael M ^a  

^a UNIVERSITY OF OREGON   (United States)

Author keywords

Alkynes; Annulene; Aromaticity

Indexed keywords

ACETYLENE DERIVATIVE; ANNULENE DERIVATIVE; COPPER; LEAD; MACROCYCLIC COMPOUND;

ARTICLE; DRUG STRUCTURE; DRUG SYNTHESIS; NUCLEAR MAGNETIC RESONANCE;

EID: 0032541708     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(98)01583-4     Document Type: Article

References (23)

1. 1. Haley, M.M. Synlett 1998, 557, and references therein.
2. 2. Inter alia: (a) Baldwin, K.P.; Matzger, A.J.; Scheiman, D.A.; Tessier, C.A.; Vollhardt, K.P.C.; Youngs, W.J. Synlett 1995, 1215.
3. (b) Boese, R.; Matzger, A.J.; Vollhardt, K.P.C. J. Am. Chem. Soc. 1997, 112, 2052.
4. (c) Tovar, J.D.; Jux, N.; Jarrosson, T.; Khan, S.I.; Rubin, Y. J. Org. Chem. 1997, 62, 3432.
5. 3. Haley, M.M.; Bell, M.; Brand, S.C.; Kimball, D.B.; Pak, J.J.; Wan, W.B. Tetrahedron Lett. 1997, 38, 7483.
6. 4. Brandsma, L. Preparative Acetylenic Chemistry, Elsevier: Amsterdam, 1988.
7. 5. (a) Haley, M.M.; Bell, M.L.; English, J.J.; Johnson, C.A.; Weakley, T.J.R. J. Am. Chem. Soc. 1997, 119, 2956.
8. (b) Haley, M.M.; Brand, S.C.; Pak, J.J. Angew. Chem., Int. Ed. Engl. 1997, 36, 836.
9. 6. Rubin, Y.; Parker, T.C.; Khan, S.I.; Holliman, C.L.; McElvany, S.W. J. Am. Chem. Soc. 1996, 118, 5308.
10. 7. de Graaf, W.; Smits, A.; Boersma, J.; van Koten, G.; Hoekstra, W.P.M. Tetrahedron 1988, 44, 6699.
11. 8. Eastmond, R.; Walton, D.M.R. Tetrahedron 1972, 28, 4591.
12. 13C NMR 132.66, 132.12, 128.18, 127.96, 125.82, 125.46, 121.93, 120.77, 105.02, 103.25, 100.69, 95.40, 93.85, 91.37, 18.68, 11.30, -0.20.
13. 10. Prepared from 1 (41% yield) in a manner analogous to 7 (Scheme 2).
14. 11. (a) Garratt, P.J. Aromaticity, Wiley: New York, 1986.
15. (b) Balaban, A.T.; Banciu, M.; Ciorba, V. Annulenes, Benzo-, Hetero-, Homo- Derivatives and their Valence Isomers, Vol. 1-3, CRC Press: Boca Raton, 1987.
16. (c) Minkin, V.I.; Glukhovtsev, M.N.; Simkin, B.Ya. Aromaticity and Antiaromaticity, Wiley: New York, 1994.
17. (d) Staab, H.A.; Günther, P. Chem. Ber. 1977, 110, 619, and references therein.
18. 12. The planarity of 4, 5, and 9 is assumed due to the fact that X-ray crystal structures of [12]-to [18]-annulene and derivatives show that the macrocyclic ring in every tribenzo-case is essentially flat. Additionally, we recently obtained a crystal structure of 10 which confirmed its planarity. This cannot be discussed here due to space limitations: Wan, W.B., Weakley, T.J.R., Haley, M.M., unpublished results.
19. d in [12]-to [16]annulene using 2D-NMR techniques. The corresponding protons in [18]-to [22]annulene were assigned by analogy. We thank Professor Vollhardt for sharing this information prior to publication.
20. d of 7.50 and 7.30 ppm, respectively. ODEB and 6 were chosen as representative examples.
21. 15. Although the acyclic precursors to the DBAs might be, in theory, better models for comparative purposes, in practice this does not work due to their comformational flexibility and thus the influence on the NMR chemical shifts by magnetic anisotropy of dangling alkyne units.
22. 16. We feel the monoene comparison is valid since the overall change in the expanded structures is minimal; however, since the effects we are attemptimg to qualify are small, this comparison might not hold true. We put forth these results in order to stimulate further discussion. See also references 11b, 11d, and 13.
23. 17. Vollhardt, K.P.C.; Winn, L.S. Tetrahedron Lett. 1985, 26, 709.