Enantioselective carbanion cyclization of 5-alkenyl carbamates induced by asymmetric lithiation with s-butyllithium/(-)-sparteine system

Tetrahedron Letters

Volumn 39, Issue 52, 1998, Pages 9715-9718

  Tomooka, Katsuhiko ^a   Komine, Nobuyuki ^a   Sasaki, Tomoya ^a   Shimizu, Hideo ^a   Nakai, Takeshi ^a  

^a TOKYO INSTITUTE OF TECHNOLOGY   (Japan)

Author keywords

Carbanions; Cyclization; Enantiocontrol; Lithiation

Indexed keywords

CARBAMIC ACID DERIVATIVE; LITHIUM DERIVATIVE;

ARTICLE; CYCLIZATION; ENANTIOMER; REACTION ANALYSIS; STEREOCHEMISTRY; SYNTHESIS;

EID: 0032564642     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(98)02233-3     Document Type: Article

References (23)

1. 1. Review on carbanion cyclization: Bailey, W. F.; Ovaska, T. V. In Advances in Detailed Reaction Mechanisms, Vol. 3, 1994, 251-273.
2. 2. a) Coldham, I.; Hufton, R.; Snowden, D. J. J. Am. Chem. Soc. 1996, 118, 5322-5323.
3. b) Tomooka, K.; Komine, N.; Nakai, T. Tetrahedron Lett. 1997, 38, 8939-8942.
4. 3. Reviews: (a) Hoppe, D.; Hense, T. Angew. Chem. Int. Ed. Engl. 1997, 36, 2282-2316.
5. (b) Beak, P.; Basu, A.; Gallageher, D. J.; Park, Y. S.; Thayumanavan, S. Acc. Chem. Res. 1996, 29, 552-560.
6. 4. This work was presented at the Annual Meeting of the Chemical Society of Japan, March, 1997, Tokyo, Abstract 3G101.
7. 5. Quite recently, Hoppe et al. have already reported a similar enantioselective carbanion cyclization of a (Z)-5-alkenyl carbamate (with different N-substituents) using s-BuLi / (-)-sparteine: Woltering, M. J.; Frölich, R.; Hoppe, D. Angew. Chem. 1997, 109, 1804-1805; Angew. Chem. Int. Ed. Engl. 1997, 36, 1764-1766.
8. 5. Quite recently, Hoppe et al. have already reported a similar enantioselective carbanion cyclization of a (Z)-5-alkenyl carbamate (with different N-substituents) using s-BuLi / (-)-sparteine: Woltering, M. J.; Frölich, R.; Hoppe, D. Angew. Chem. 1997, 109, 1804-1805; Angew. Chem. Int. Ed. Engl. 1997, 36, 1764-1766.
9. 6. Initially, we attempted the carbanion cyclization of the 5-hexenol carbamate, however, no cyclization product was obtained.
10. 7. Note that the combined use of 1.5 equiv. of s-BuLi and 1.5 equiv. of (-)-sparteine gave 2a in 13% yield.
11. 3)
12. 1H NMR analysis: cf. Lit. Casey, P.; Polichnowski, W.; Shusterman, J.; Jones, R. J. Am. Chem. Soc. 1979, 101, 7282-92.
13. 10. Recently we have found that treatment of alkyl N,N-diisopropyl carbamates with DIBAL in ether affords the corresponding alcohol in high yields: Unpublished results (Shimizu, H. MS Thesis, Tokyo Institute of Technology, 1997).
14. 11. Seemayer, R.; Schneider, M. P. Recl. Trav. Chim. Pays-Bas 1991, 110, 171-174.
15. 12. For similar cyclopropane formations in organolithium reactions, see: Paetow, M.; Kotthaus, M.; Grehl, M.; Frölich, R.; Hoppe, D. Synlett 1994, 1034-1036. Krief, A.; Hobe. M.; Dumont, W.; Badaoui, E.; Guittet, E.; Evard, G. Tetrahedron Lett. 1992, 33, 3381-3384. Krief, A.; Hobe. M. Tetrahednm Lett. 1992, 33, 6527-6530, 6529-6532.
16. 12. For similar cyclopropane formations in organolithium reactions, see: Paetow, M.; Kotthaus, M.; Grehl, M.; Frölich, R.; Hoppe, D. Synlett 1994, 1034-1036. Krief, A.; Hobe. M.; Dumont, W.; Badaoui, E.; Guittet, E.; Evard, G. Tetrahedron Lett. 1992, 33, 3381-3384. Krief, A.; Hobe. M. Tetrahednm Lett. 1992, 33, 6527-6530, 6529-6532.
17. 12. For similar cyclopropane formations in organolithium reactions, see: Paetow, M.; Kotthaus, M.; Grehl, M.; Frölich, R.; Hoppe, D. Synlett 1994, 1034-1036. Krief, A.; Hobe. M.; Dumont, W.; Badaoui, E.; Guittet, E.; Evard, G. Tetrahedron Lett. 1992, 33, 3381-3384. Krief, A.; Hobe. M. Tetrahednm Lett. 1992, 33, 6527-6530, 6529-6532.
18. 2 symmetrical diol 8, as depicted below. (equation presented)
19. w=0.052 (Fig.1). (equation presented) Fig. 1 ORTEP representation of 9
20. 15. Quite recently, Hoppe's group has reported that an appreciable level of kinetic resolution is not observed in the s-BuLi / (-)-sparteine-induced cyclization of a 4-substituted 5-hexynyl carbamate: Oestreich, M.; Fröhlich, R.; Hoppe, D. Tetrahedron Lett. 1998, 39, 1745-1748.
21. N2-type cyclization, whereas conformer i v preferred for (3R)-6b is well suited for the cyclopropane formation. (equation presented)
22. 17. It is worth noting that, the yield and stereopurity of 7 were highly dependent on the amounts of (-)-sparteine and s-BuLi.
23. 18. Similar 5-exo cyclization / substitution reaction was reported by Hoppe's group: see ref. 5.