Carbanion cyclisation of esters. Part 2: Enantiospecific construction of the tricyclic framework of the marine sesquiterpenes, spirodysins

Tetrahedron Letters

Volumn 45, Issue 2, 2004, Pages 383-386

  Srikrishna, A ^a   Ravi Kumar, P ^a   Ramasastry, S S V ^a  

^a INDIAN INSTITUTE OF SCIENCE   (India)

Author keywords

[No Author keywords available]

Indexed keywords

AMMONIA; BICYCLO[4.3.0]NONAN 8 ONE; ESTER DERIVATIVE; KETONE DERIVATIVE; LITHIUM; NATURAL PRODUCT; SESQUITERPENE DERIVATIVE; UNCLASSIFIED DRUG;

ANNULATION REACTION; ARTICLE; CHEMICAL ANALYSIS; CLAISEN REARRANGEMENT; COLUMN CHROMATOGRAPHY; CRYSTAL STRUCTURE; CYCLIZATION; ENANTIOSELECTIVITY; EPOXIDATION; HORNER WADSWORTH EMMONS REACTION; LIQUID; OXIDATION; RADICAL REACTION; REDUCTION; STRUCTURE ANALYSIS;

EID: 0346995408     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tetlet.2003.10.165     Document Type: Article

References (16)

1. Srikrishna, A.; Ramasastry, S. S. V. Tetrahedron Lett. 2003, 44, see doi:10.1016/j.tetlet.2003.10.164.
2. Goetz G.H., Harrigan G.G., Likos J. J. Nat. Prod. 64:2001;1486-1488.
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8. To the best of our knowledge there is no report in the literature on the synthesis of spirodysins either in racemic or optically active forms.
9. Johnson W.S., Werthemann L., Bartlett W.R., Brocksom T.J., Li T.t., Faulkner D.J., Petersen M.R. J. Am. Chem. Soc. 92:1970;741-743.
10. Giese B., Kopping B., Gobel T., Dickhaut G., Thoma G., Kulicke K.J., Trach F. Org. React. 48:1996;301 Renaud P., Sibi M.P. Radicals in Organic Synthesis. Vols. 1 and 2:2001;Wiley-VCH.
11. Giese B., Kopping B., Gobel T., Dickhaut G., Thoma G., Kulicke K.J., Trach F. Org. React. 48:1996;301 Renaud P., Sibi M.P. Radicals in Organic Synthesis. Vols. 1 and 2:2001;Wiley-VCH.
12. In contrast, reaction of the ester i , containing an extra methyl group at the benzylic position, in liquid ammonia with lithium followed by oxidation of the resulting mixture of alcohols furnished 1:3 mixture of the aldehyde ii and the tetralone iii containing a small amount of α-cuparenone iv, in 86% yield, perhaps due to the steric crowding of two vicinal quaternary carbon atoms in the cuparanes.
13. The structure of the alcohol 14 was established from its spectral data and was further confirmed by single crystal X-ray diffraction analysis of the corresponding 4-nitrobenzoate ester. The crystallographic data has been deposited with the Cambridge Crystallographic Data Center (CCDC 218889).
14. It is worth mentioning that the radical cyclisation of the iodide v , obtained from the ester 13 in two steps, produced a 2:1 (by NMR) mixture of the 5-exo trig and 6-endo-trig cyclisation products vi and vii.
15. Part 59: Srikrishna A., Kumar P.P., Reddy T.J. Arkivoc. iii:2003;55-66. Part 60: Srikrishna A., Dethe D.H. Tetrahedron Lett. 44:2003;7817-7820.
16. Part 59: Srikrishna A., Kumar P.P., Reddy T.J. Arkivoc. iii:2003;55-66. Part 60: Srikrishna A., Dethe D.H. Tetrahedron Lett. 44:2003;7817-7820.