Enantioselective reactions of radicals at the α position of γ-lactams

Tetrahedron Letters

Volumn 40, Issue 37, 1999, Pages 6713-6716

  Porter, Ned A ^a,b   Feng, Hao ^a,b   Kavrakova, Ivanka K ^a,b  

^a DUKE UNIVERSITY   (United States)

^b VANDERBILT UNIVERSITY   (United States)

Author keywords

Lactams; Addition reactions; Enantioselection; Lewis acids; Oxazolidinones; Radical reactions; Radicals

Indexed keywords

2 AMINOPYRIDINE DERIVATIVE; FREE RADICAL; GAMMA LACTAM DERIVATIVE; OXAZOLIDINONE DERIVATIVE; SILANE DERIVATIVE;

ALKALINITY; ARTICLE; CHEMICAL MODIFICATION; CHEMICAL REACTION; CHIRALITY; ENANTIOMER; REACTION ANALYSIS; STRUCTURE ANALYSIS;

EID: 0033543727     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(99)01370-2     Document Type: Article

References (14)

1. For a discussion of acyclic diastereoselection in radical reactions see: (a) Sibi, M. P.; Porter, N. A. Acc. Chem. Res. 1999, 32, 163-171.
2. (b) Curran, D. P.; Porter, N. A.; Giese, B. Stereochemistry of Radical Reactions; VCH: Weinheim, 1995.
3. (c) Porter, N. A.; Giese, B.; Curran, D. P. Acc. Chem. Res. 1991, 24, 296-301.
4. (d) Smadja, W. Synlett 1994, 1-26.
5. (a) Porter, N. A.; Wu, J. H.; Zhang, G.; Reed, A. D. J. Org. Chem. 1997, 62, 6702-6703.
6. See also: (b) Wu, J. H.; Zhang, G.; Porter, N. A. Tetrahedron Lett. 1997, 38, 2067-2070.
7. 13C), elemental analysis or accurate mass determination. For the preparation of 2,4-dibromobutyryl bromide see: Philips, B. A; Cromwell, N. H. J. Heterocycl. Chem. 1973, 795-799 and Adams, R.; Ulich, L. H. J. Am. Chem. Soc. 1920, 42, 599-611.
8. 13C), elemental analysis or accurate mass determination. For the preparation of 2,4-dibromobutyryl bromide see: Philips, B. A; Cromwell, N. H. J. Heterocycl. Chem. 1973, 795-799 and Adams, R.; Ulich, L. H. J. Am. Chem. Soc. 1920, 42, 599-611.
9. For typical conditions for the conversion of the acid bromide to 6 see: Okawara, T.; Matsuda, T.; Furukawa, M. Chem. Pharm. Bull. 1982, 30, 1225-1233.
10. 2O. The crude product was purified by flash column chromatography (1:9, ethyl acetate:hexane). Isolated yields are comparable to those determined by internal standard.
11. Sibi, M. P.; Ji, J. J. Org. Chem. 1996, 61, 6090-6091.
12. Ligand 2b and 1 give products with very low enantiomeric excess in reactions promoted by Mg Lewis acids.
13. Ref. 2a, see also: Wu, J. H.; Radinov, R.; Porter, N. A. J. Am. Chem. Soc. 1995, 117, 11029-11030.
14. Sibi, M. P.; Shay, J. J.; Ji, J. Tetrahedron Lett. 1997, 38, 5955-5958.