Collect. Czech. Chem. Commun. 2008, 73, 786-794

The Concerted Nature of the Enzymatic Cyclization of Rings A-D of Squalene to Hopene

B. Andes Hess, Jr.a,* and Lidia Smenteka,b

a Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, U.S.A.
b Institute of Physics, N. Copernicus University, 87-100 Toruń, Poland


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5. Calculations were performed with the DFT method using: Frisch M. J., Trucks G. W., Schlegel H. B., Scuseria G. E., Robb M. A., Cheeseman J. R., Zakrzewski V. G., Montgomery J. A., Jr., Stratmann R. E., Burant J. C., Dapprich S., Millam J. M., Daniels A. D., Kudin K. N., Strain M. C., Farkas O., Tomasi J., Barone V., Cossi M., Cammi R., Mennucci B., Pomelli C., Adamo C., Clifford S., Ochterski J., Petersson G. A., Ayala P. Y., Cui Q., Morokuma K., Malick D. K., Rabuck A. D., Raghavachari K., Foresman J. B., Cioslowski J., Ortiz J. V., Stefanov B. B., Liu G., Liashenko A., Piskorz P., Komaromi I., Gomperts R., Martin R. L., Fox D. J., Keith T., Al-Laham M. A., Peng C. Y., Nanayakkara A., Gonzalez C., Challacombe M., Gill P. M. W., Johnson B., Chen W., Wong M. W., Andres J. L., Gonzalez C., Head-Gordon M., Replogle E. S., Pople J. A.: Gaussian 98W. Gaussian, Inc., Pittsburgh (PA) 1998. Becke’s three-parameter hybrid method (ref.5) with the Lee–Yang–Parr correlation function (ref.6) and the 6-31G* basis set (ref.7) were employed.
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9. Calculation of the second derivative of the energy of 2 confirmed it to be a minimum on the potential surface.
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13. In the recent report: Vrcek V.: Int. J. Quantum Chem. 2007, 107, 1772, it has been shown that there are other possible rearrangement pathways for carbocation 20; however, these are unlikely to play a role in the cyclization of squalene because of conformational effects, which are so important in the enzyme catalyzed cyclization of squalene. <>
14. Morikubo N., Fukuda Y., Ohtake K., Shinya N., Kiga D., Sakamoto K., Asanuma M., Hirota H., Yokoyama S., Hoshino T.: J. Am. Chem. Soc. 2006, 128, 13184. <>