Origin of stereoselectivity in the (4 + 3) cycloadditions of chiral alkoxy siloxyallyl cations with furan

Organic Letters

Volumn 12, Issue 3, 2010, Pages 444-447

  Krenske, Elizabeth H ^a   Houk, K N ^a   Harmata, Michael ^b  

^a UNIVERSITY OF CALIFORNIA   (United States)

^b UNIVERSITY OF MISSOURI   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 75749089181     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol902591k     Document Type: Article

References (17)

1. (a) Hoffmann, H. M. R. Angew. Chem., Int. Ed. Engl. 1984, 23, 1-19.
2. (b) Harmata, M.; Rashatasakhon, P. Tetrahedron 2003, 59, 2371-2395.
3. Murray, D. H.; Albizati, K. F. Tetrahedron Lett. 1990, 31, 4109-4112.
4. (a) Stark, C. B. W.; Eggert, U.; Hoffmann, H. M. R. Angew. Chem., Int. Ed. 1998, 37, 1266-1268.
5. (b) Stark, C. B. W.; Pierau, S.; Wartchow, R.; Hoffmann, H. M. R. Chem.-Eur. J. 2000, 6, 684-691.
6. Hoffmann introduced the terms "compact" and "extended" to describe the geometries of (4 + 3) cycloadditions. See: Hoffmann, H. M. R. Angew. Chem., Int. Ed. 1973, 12, 819-835.
7. In ref 3b, the S enantiomer was used for the Ph-containing oxyallyl cation, but the R enantiomer was used for the 2-naphthyl-containing cation. The cycloadduct for the 2-naphthyl case was therefore enantiomeric to 3a.
8. Krenske, E. H.; Houk, K. N.; Lohse, A. G.; Antoline, J. E.; Hsung, R. P., submitted.
9. Xiong, H.; Hsung, R. P.; Berry, C. R.; Rameshkumar, C. J. Am. Chem. Soc. 2001, 123, 7174-7175.
10. Frisch, M. J. Gaussian 03, Revision C.02; Gaussian, Inc.; Wallingford, CT, 2004.
11. (a) Barone, V.; Cossi, M. J. Phys. Chem. A 1998, 102, 1995-2001.
12. (b) Barone, V.; Cossi, M.; Tomasi, J. J. Comput. Chem. 1998, 19, 404-417.
13. Wheeler, S. E.; Houk, K. N. Mol. Phys. 2009, 107, 749-760.
14. M06-2X/6-31G (d) calculations were carried out in NWChem 5.1.1 using the xfine grid: Bylaska, E. J. et al. NWChem, A Computational Chemistry Package for Parallel Computers, version 5.1.1; Pacific Northwest National Laboratory: Richland, WA, 2009.
15. Zhao, Y.; Truhlar, D. G. Acc. Chem. Res. 2008, 41, 157-167.
16. Beck, H.; Stark, C. B. W.; Hoffmann, H. M. R. Org. Lett. 2000, 2, 883-886.
17. The benzylic carbon in TS2a-c has the S configuration, while the experimental study in reference 13 employed the R enantiomer. Taking this into account, TSs analogous to TS-2a correspond to the experimental cycloadduct 4a, and TSs analogous to TS-2b/c correspond to cycloadduct 4b.