Enantioselective indole Friedel-Crafts alkylations catalyzed by bis(oxazolinyl)pyridine-scandium(III) triflate complexes

Journal of the American Chemical Society

Volumn 125, Issue 36, 2003, Pages 10780-10781

  Evans, David A ^a   Scheidt, Karl A ^a,b   Fandrick, Keith R ^a   Lam, Hon Wai ^a   Wu, Jimmy ^a  

^a HARVARD UNIVERSITY   (United States)

^b NORTHWESTERN UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

BIS(OXAZOLINYL)PYRIDINE; INDOLE DERIVATIVE; LEWIS ACID; METAL COMPLEX; PYRIDINE DERIVATIVE; SCANDIUM; UNCLASSIFIED DRUG;

ALKYLATION; ARTICLE; CATALYSIS; CHELATION; CHEMICAL BOND; CHEMICAL STRUCTURE; CHIRALITY; ENANTIOSELECTIVITY; FRIEDEL CRAFTS REACTION; REACTION ANALYSIS; ROOM TEMPERATURE; STRUCTURE ANALYSIS;

ALKYLATION; CATALYSIS; INDOLES; MESYLATES; MODELS, MOLECULAR; OXAZOLES; PHOSPHONIC ACIDS; PYRIDINES; SCANDIUM; STEREOISOMERISM;

EID: 0042233997     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja036985c     Document Type: Article

References (21)

1. For a general review of Friedel-Crafts reactions, see: Olah, G. A.; Krishnamurti, R.; Prakash, G. K. S. Friedel-Crafts Alkylations. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon Press: Oxford, 1991; Vol. 3, pp 293-339.
2. (a) For Cu(II)-catalyzed additions of aromatic systems to unsaturated ester derivatives, see: Jensen, K. B.; Thorbauge, J.; Hazell, R. G.; Jorgensen, K. A. Angew. Chem., Int. Ed. 2001, 40, 160-163. Zhou, J.; Tang, Y. J. Am. Chem. Soc. 2002, 124, 9030-9031.
3. (a) For Cu(II)-catalyzed additions of aromatic systems to unsaturated ester derivatives, see: Jensen, K. B.; Thorbauge, J.; Hazell, R. G.; Jorgensen, K. A. Angew. Chem., Int. Ed. 2001, 40, 160-163. Zhou, J.; Tang, Y. J. Am. Chem. Soc. 2002, 124, 9030-9031.
4. (b) For additions of electron-rich benzenes and indoles to α,β-unsaturated aldehydes catalyzed by chiral secondary amines, see: Paras, N. A.; MacMillan, D. W. C. J. Am. Chem. Soc. 2001, 123, 4370-4371. Austin, J. F.; MacMillan, D. W. C. J. Am. Chem. Soc. 2002, 124, 1172-1173.
5. (b) For additions of electron-rich benzenes and indoles to α,β-unsaturated aldehydes catalyzed by chiral secondary amines, see: Paras, N. A.; MacMillan, D. W. C. J. Am. Chem. Soc. 2001, 123, 4370-4371. Austin, J. F.; MacMillan, D. W. C. J. Am. Chem. Soc. 2002, 124, 1172-1173.
6. (a) Evans, D. A.; Sweeney, Z. K.; Rovis, T.; Tedrow, J. S. J. Am. Chem. Soc. 2001, 123, 12095-12096.
7. (b) Evans, D. A.; Masse, C. E.; Wu, J. Org. Lett. 2002, 4, 3375-3378.
8. (c) Evans, D. A.; Wu, J.; Masse, C. E.; MacMillan, D. W. C. Org. Lett. 2002, 4, 3379-3382.
9. For the application of a chiral scandium catalyst in Diels-Alder reactions, see: (a) Kobayashi, S.; Araki, M.; Hachiya, I. J. Org. Chem. 1994, 59, 3758. (b) Quian, C.; Wang, L. Tetrahedron Lett. 2000, 41, 2203. For a review of scandium(III) triflate-catalyzed reactions, see: Kobayashi, S. Eur. J. Org. Chem. 1999, 15-27.
10. For the application of a chiral scandium catalyst in Diels-Alder reactions, see: (a) Kobayashi, S.; Araki, M.; Hachiya, I. J. Org. Chem. 1994, 59, 3758. (b) Quian, C.; Wang, L. Tetrahedron Lett. 2000, 41, 2203. For a review of scandium(III) triflate-catalyzed reactions, see: Kobayashi, S. Eur. J. Org. Chem. 1999, 15-27.
11. For the application of a chiral scandium catalyst in Diels-Alder reactions, see: (a) Kobayashi, S.; Araki, M.; Hachiya, I. J. Org. Chem. 1994, 59, 3758. (b) Quian, C.; Wang, L. Tetrahedron Lett. 2000, 41, 2203. For a review of scandium(III) triflate-catalyzed reactions, see: Kobayashi, S. Eur. J. Org. Chem. 1999, 15-27.
12. Sc(S,S)-Ph-pybox = [(S)-(R*,R* )]-2,6-bis(4,5-dihydro-4-phenyl-2-oxazolyl)-pyridine. Davies, I. W.; Gerena, L. ; Lu, N.; Larsen, R. D.; Reider, P. J. J. Org. Chem. 1996, 61, 9629-9630.
13. For the use of α,β-unsaturated acyl phosphonates in Lewis acid-catalyzed reactions, see: (a) Telan, L. A.; Poon, C.-D.; Evans, S. A., Jr. J. Org. Chem. 1996, 61, 7455-7462. (b) Evans, D. A.; Johnson, J. S.; Olhava, E. J. J. Am. Chem. Soc. 2000, 122, 1635-1649.
14. For the use of α,β-unsaturated acyl phosphonates in Lewis acid-catalyzed reactions, see: (a) Telan, L. A.; Poon, C.-D.; Evans, S. A., Jr. J. Org. Chem. 1996, 61, 7455-7462. (b) Evans, D. A.; Johnson, J. S.; Olhava, E. J. J. Am. Chem. Soc. 2000, 122, 1635-1649.
15. Dialkyl acyl phosphonates are highly effective acylating agents. Sekine, M.; Kume, A.; Hata, T. Tetrahedron Lett. 1981, 22, 3617-3620.
16. (a) Saxton, J. E. Nat. Prod. Rep. 1997, 14, 559-590.
17. (b) Toyota, M.; Ihara, N. Nat. Prod. Rep. 1998, 15, 327-340 and references therein.
18. Only alkylation at the 3-position of the indole structure was observed.
19. Substitution at the 2-position only slightly affects enantioselectivity, e.g., for 1,2-dimethylindole addition to 2a, 86% ee, 94% yield.
20. For examples of additions to morpholine amides, see: Douat, C.; Heitz, A.; Martinez, J.; Fehrentz, J.-A. Tetrahedron Lett. 2000, 41, 37-40 and references therein.
21. 2O were accessed with ChemBats3D Pro (version 7.0). The two vicinal triflates and water molecule were replaced by the acyl phosphonate, and the molecular energy was minimized (MM2) with the ligand-metal bonds held constant.