Highly enantioselective [4 + 2] cycloaddition reactions catalyzed by a chiral N-methyl-oxazaborolidinium cation

Organic Letters

Volumn 10, Issue 15, 2008, Pages 3271-3273

  Canales, Eda ^a   Corey, E J ^a  

^a HARVARD UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ALKADIENE; AMINOALCOHOL; BORON DERIVATIVE; CATION; CYCLOPENTANE DERIVATIVE; CYCLOPENTENONE; HETEROCYCLIC COMPOUND;

ARTICLE; CHEMISTRY; CYCLIZATION; STEREOISOMERISM; SYNTHESIS;

ALKADIENES; AMINO ALCOHOLS; AZA COMPOUNDS; BORON COMPOUNDS; CATIONS; CYCLIZATION; CYCLOPENTANES; STEREOISOMERISM;

EID: 49649124668     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol8011502     Document Type: Article

References (20)

1. For a review, see: Corey, E. J.; Helal, C. J. Angew. Chem., Int. Ed. 1998, 37, 1986-2012.
2. For a recent application, see: (a) Yeung, Y.-Y.; Chein, R.-J.; Corey, E. J. J. Am. Chem. Soc. 2007, 129, 10346-10347.
3. See also: (b) Hu, Q.-Y.; Zhou, G.; Corey, E. J. J. Am. Chem. Soc. 2004, 126, 13708-13713.
4. (a) Corey, E. J.; Shibata, T.; Lee, T. W. J. Am. Chem. Soc. 2002, 124, 3808-3809.
5. (b) Ryu, D. H.; Lee, T. W.; Corey, E. J. J. Am. Chem. Soc. 2002, 124, 9992-9993.
6. (c) Ryu, D. H.; Corey, E. J. J. Am. Chem. Soc. 2003, 125, 6388-6390.
7. (d) Ryu, D. H.; Zhou, G.; Corey, E. J. J. Am. Chem. Soc. 2004, 126, 4800-4802.
8. (e) Zhou, G.; Hu, Q.-Y.; Corey, E. J. Org. Lett. 2003, 5, 3979-3982.
9. (f) Snyder, S. A.; Corey, E. J. J. Am. Chem. Soc. 2006, 128, 740-742.
10. (g) Hong, S.; Corey, E. J. J. Am. Chem. Soc. 2006, 128, 1346-1352.
11. (h) Yeung, Y.-Y.; Hong, S.; Corey, E. J. J. Am. Chem. Soc. 2006, 128, 6310-6311.
12. (i) Zhou, G.; Corey, E. J. J. Am. Chem. Soc. 2005, 127, 11958-11959.
13. (j) Liu, D.; Canales, E.; Corey, E. J. J. Am. Chem. Soc. 2007, 129, 1498-1499.
14. Canales, E.; Corey, E. J. J. Am. Chem. Soc. 2007, 129, 12686-12687.
15. Zhou, G.; Corey, E. J. J. Am. Chem. Soc. 2005, 127, 11958-11959.
16. Liu, D.; Hong, S.; Corey, E. J. J. Am. Chem. Soc. 2006, 128, 8160-8161.
17. The lithium o-tolylborohydride was prepared using a modification of H. C. Brown's procedure: Singaram, B.; Cole, T. E.; Brown, H. C. Organometallics 1984, 3, 774-777.
18. 11B NMR shows a shift from (δ) +7.7 for 5 to +34 for 3.
19. See Supporting Information.
20. For comparison, the triflimide cationic catalyst 2, X = H, afforded 16 in 85% yield and 78% ee.