Heck reaction of endocyclic enecarbemates with diazonium salts. Formal enantioselective syntheses of alkaloids (-)-codonopsine and (-)- codonopsinine, and the synthesis of a new C-aryl azasugar

Tetrahedron Letters

Volumn 40, Issue 11, 1999, Pages 2083-2086

  Oliveira, Denilson F ^a,b   Severino, Elias A ^a   Correia, Carlos Roque D ^a  

^a UNIVERSITY OF CAMPINAS   (Brazil)

^b FEDERAL UNIVERSITY OF LAVRAS   (Brazil)

Author keywords

Alkaloids; Enecarbamates; Heck reactions; Pyrrolidines

Indexed keywords

ALKALOID; CARBAMIC ACID DERIVATIVE; CODONOPSINE; CODONOPSININE; DIAZONIUM COMPOUND; UNCLASSIFIED DRUG;

ARTICLE; CARBON NUCLEAR MAGNETIC RESONANCE; CENTRAL NERVOUS SYSTEM; DRUG SYNTHESIS; ENANTIOMER; EPOXIDATION; PROTON NUCLEAR MAGNETIC RESONANCE; REACTION ANALYSIS; SPECTROSCOPY;

EID: 0033548526     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(99)00151-3     Document Type: Article

References (17)

1. For reviews on the Heck reaction see: (a) de Meijere, A.; Meyer, F. E. Angew. Chem. Int. Ed. Engl. 1994, 36, 2379-2411.
2. (b) Cabri, W.; Candiani, E. Acc. Chem. Res. 1995, 28:2-7.
3. Examples on the use of enecarbamates in synthesis: (a) Sugisaki, C. H.; Carroll, P. J.; Correia, C. R. D. Tetrahedron Lett. 1998, 39, 3413-3416.
4. (b) Carpes, M. J. S.; Miranda, P. C. M. L.; Correia, C. R. D. Tetrahedron Lett. 1997, 38, 1869-1872.
5. (c) Bueno, A. B.; Hegedus, L. S. J. Org. Chem. 1998, 63, 684-690.
6. (d) Paquette, L. A.; Tae, J. Tetrahedron Lett. 1997, 38, 3151-3154.
7. Enecarbamates 4 and 5 were prepared from (S)-pyroglutamic acid in 5 steps (overall yield of 52-70%) by a protocol featuring a dehydration of α-hydroxycarbamates promoted by TFAA/2,6-lutidine (manuscript sent for publication). Enantiomeric purity was checked by chiral HPLC (Chiracel OD) and shown to be >98% ee.
8. Yoda, H.; Nakajima, T.; Takabe, K. Tetrahedron Lett. 1996, 37, 5531-5534 and references cited therein.
9. For a leading reference, see: Sengupta, S.; Sadhukhan, S. K.; Bhattacharyya, S. Tetrahedron 1997, 53, 2213-2218.
10. Heck reaction of endocyclic enecarbamates and enamides have been carried out before employing aryl triflates and iodides. Usually a large excess of enecarbamate/enamide (up to fivefold) is required for good yields in intermolecular Heck reactions. For some examples see: (a) Fumiyuki, O.; Kobatake, Y.; Hayashi, T. Tetrahedron Lett. 1993, 34, 2505-2508.
11. (b) Sonesson, C.; Larhed, M.; Nyqvist, C.; Hallberg, A.; J. Org. Chem 1996, 61, 4756-4763.
12. (c) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965-4968 (intramolecular Heck reaction).
13. (d) Fumiyuki, O.; Hayashi, T. J. Organomet. Chem. 1992, 428, 267-277.
14. Wang, C. L. J.; Calabrese, J. C. J. Org. Chem. 1991, 56, 4341-4343 (see supplementary material).
15. For an review on this subject, see: Hoveyda, A. H.; Evans, D. A.; Fu, G. C. Chem. Rev. 1993, 93, 1307-1370.
16. (a) Wang, Y. F.; Dumas, D. P.; Wong, C. H. Tetrahedron Lett. 1993, 34, 403-406.
17. (b) Molyneux, R. J.; Pan, Y. T.; Tropea, J. E.; Elbein, A. D.; Lawyer, C. H.; Hughes, D. J.; Fleet, G. W. J. J. Nat. Prod. 1993, 56, 1356-1364.