Thermodynamic control of the electrocyclic ring opening of cyclobutenes: CdX substituents at C-3 mask the kinetic torquoselectivity

Journal of the American Chemical Society

Volumn 131, Issue 19, 2009, Pages 6664-6665

  Um, Joann M ^a   Xu, Huadong ^b   Houk, K N ^a   Tang, Weiping ^b  

^a UNIVERSITY OF CALIFORNIA   (United States)

^b UNIVERSITY OF WISCONSIN MADISON   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

AROMATIC HYDROCARBONS; BUTENES; HYDROCARBONS; ROTATION; STEREOSELECTIVITY; THERMODYNAMICS;

CHEMICAL EQUATIONS; DIESTER; ELECTROCYCLIC REACTIONS; ELECTROCYCLIC RINGS; METHYL GROUP; PHENYL GROUP; PHENYL SUBSTITUENTS; RING OPENING REACTION; THERMODYNAMIC CONTROL; TORQUOSELECTIVITY;

DENSITY FUNCTIONAL THEORY;

CYCLOBUTANE DERIVATIVE; ESTER DERIVATIVE; PYRAN DERIVATIVE; 1-ETHOXYCARBONYL-4-PHENYLCYCLOBUTENE; 4-METHYL-1,3,3-TRIETHOXYCARBONYLCYCLOBUTENE; 4-PHENYL-1,3,3-TRIETHOXYCARBONYLCYCLOBUTENE;

ARTICLE; BIOLOGY; CALCULATION; ENTHALPY; ISOMERIZATION; KINETICS; PROTON NUCLEAR MAGNETIC RESONANCE; RING OPENING; STRUCTURE ANALYSIS; THERMODYNAMICS; CHEMISTRY; CYCLIZATION; STEREOISOMERISM;

CYCLIZATION; CYCLOBUTANES; STEREOISOMERISM; THERMODYNAMICS;

EID: 67650559127     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja9016446     Document Type: Article

References (25)

1. (a) Woodward, R. B.; Hoffmann, R. J. Am. Chem. Soc. 1965, 87, 395-397.
2. (b) Woodward, R. B.; Hoffmann, R. The Conservation of Orbital Symmetry; Academic Press: New York, 1970.
3. (a) Kirmse, W.; Rondan, N. G.; Houk, K. N. J. Am. Chem. Soc. 1984, 106, 7989-7991.
4. (b) Rondan, N. G.; Houk, K. N. J. Am. Chem. Soc. 1985, 107, 2099-2111.
5. (c) Rudolf, K.; Spellmeyer, D. C.; Houk, K. N. J. Org. Chem. 1987, 52, 3708-3710.
6. (d) Houk, K. N.; Spellmeyer, D. C.; Jefford, C. W.; Rimbault, C. G.; Wang, Y.; Miller, R. D. J. Org. Chem. 1988, 53, 2125-2127.
7. (e) Niwayama, S.; Kallel, E. A.; Spellmeyer, D. C.; Sheu, C.; Houk, K. N. J. Org. Chem. 1996, 61, 2813-2825.
8. (f) Dolbier, W. R., Jr.; Koroniak, H.; Houk, K. N.; Sheu, C. Acc. Chem. Res. 1996, 29, 471-477.
9. (g) Murakami, M.; Miyamoto, Y.; Ito, Y. Angew. Chem., Int. Ed. 2001, 40, 189-190.
10. (h) Shindo, M.; Matsumoto, K.; Mori, S.; Shishido, K. J. Am. Chem. Soc. 2002, 124, 6840-6841.
11. (i) Lee, P. S.; Zhang, X.; Houk, K. N. J. Am. Chem. Soc. 2003, 125, 5072-5079.
12. (j) Murakami, M.; Hasegawa, M.; Igawa, H. J. Org. Chem. 2004, 69, 587-590.
13. (k) Murakami, M.; Usui, I.; Hasegawa, M.; Matsuda, T. J. Am. Chem. Soc. 2005, 127, 1366-1367.
14. For the syntheses of the cyclobutenes 1a* and 1c*, see: Xu, H.; Zhang, W.; Shu, D.; Werness, J. B.; Tang, W. Angew. Chem., Int. Ed. 2008, 47, 8933-8936. The ring-opening reactions described in the current manuscript are reported for the first time (see the Supporting Information). Cyclobutene 1b* could not be isolated. When the precursor cyclopropane diazoacetate S1 is treated with 5 mol % AgOTf at room temperature, the proposed cyclobutene directly undergoes ring opening to form diene 2b*. The low ring-opening activation enthalpy of 1b* (Table 1, entry 2) supports these results.
15. For examples of outward 3-Ph rotation, see: (a) Murakami, M.; Miyamoto, Y.; Ito, Y. J. Am. Chem. Soc. 2001, 123, 6441-6442.
16. (b) Shindo, M.; Sato, Y.; Yoshikawa, T.; Koretsune, R.; Shishido, K. J. Org. Chem. 2004, 69, 3912-3916.
17. (c) ref 2h.
18. (a) All of the structures were optimized in the gas phase using density functional theory [B3LYP/6-31G(d)] as implemented in the Gaussian 03 suite of programs (Frisch, M. J.; et al. Gaussian 03, revision C.02; Gaussian, Inc.: Wallingford, CT, 2004). All of the stationary points were verified as minima or first-order saddle points by vibrational frequency analysis.
19. (b) Required thermal corrections were applied to the single-point energy calculations using M06/6-31+G(d), as implemented in Q-Chem (Shao, Y.; et al. Q-Chem, version 3.0.0.6; Q-Chem, Inc.: Pittsburgh, PA, 2007). These energies are given in the text, tables, and figures.
20. The "guess)(mix, always)"
21. Niwayama, S.; Houk, K. N. Tetrahedron Lett. 1992, 33, 883-886.
22. (a) Birney, D. M. J. Org. Chem. 1996, 61, 243-251.
23. (b) Rodríguez-Otero, J. J. Org. Chem. 1999, 64, 6842-6848.
24. (a) Evanseck, J. D.; Thomas, B. E.; Spellmeyer, D. C.; Houk, K. N. J. Org. Chem. 1995, 60, 7134-7141.
25. (b) Akerling, Z. R.; Norton, J. E.; Houk, K. N. Org. Lett. 2004, 6, 4273-4275.