Samarium diiodide mediated 6-exo cyclisations of methylenecyclopropyl ketones

Tetrahedron Letters

Volumn 45, Issue 10, 2004, Pages 2223-2225

  Underwood, Jonathan J ^a   Hollingworth, Gregory J ^b   Horton, Peter N ^a   Hursthouse, Michael B ^a   Kilburn, Jeremy D ^a  

^a UNIVERSITY OF SOUTHAMPTON   (United Kingdom)

^b NEUROSCIENCE RESEARCH CENTRE   (United Kingdom)

Author keywords

Methylenecyclopropane; Radical cyclisation; Samarium diiodide

Indexed keywords

CYCLOPROPANE DERIVATIVE; KETONE DERIVATIVE; SAMARIUM DIIODIDE;

ARTICLE; CYCLIZATION; PRECURSOR; PRODUCTIVITY; STEREOCHEMISTRY;

EID: 1242272907     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tetlet.2003.12.156     Document Type: Article

References (17)

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4. Saint-Dizier A., Kilburn J.D. Tetrahedron Lett. 43:2002;6201-6203.
5. For reviews on samarium diiodide mediated radical reactions see: Steel P.G. J. Chem. Soc., Perkin Trans. 1. 2003;2727-2751.
6. Molander G.A., Harris C.R. Tetrahedron. 54:1998;3321-3354.
7. Boffey R.J., Santagostino M., Whittingham W.G., Kilburn J.D. Chem. Commun. 1998;1875-1876.
8. Boffey R.J., Whittingham W., Kilburn J.D. J. Chem. Soc., Perkin Trans. 1. 2001;487-496.
9. For previous studies on 6-exo/7-endo malonyl radical cyclisations of methylenecyclopropane derivatives, see: Destabel C., Kilburn J.D., Knight J. Tetrahedron. 50:1994;11267-11288.
10. Destabel C., Kilburn J.D., Knight J. Tetrahedron. 50:1994;11289-11302.
11. Molander G.A., McKie J.A. J. Org. Chem. 60:1995;872-878.
12. tBuOH-HMPA in related 5-exo cyclisations, but use of THF-MeOH solvent systems was not successful for the 6-exo cyclisations described herein. See Ref. [1c] and Johnston D., McCusker C.M., Procter D.J. Tetrahedron Lett. 40:1999;4913-4916.
13. 13C NMR, MS and IR. All of the cyclisation products 7 , 9-11 , 13-15 and 17 were obtained as single diastereoisomers, but the stereochemistry of the tertiary alcohol stereocentre was not determined. Compound 18 was obtained as a 3:2 mixture of E and Z vinyl silanes.
14. 8-endo Cyclisations of samarium diiodide derived ketyl radicals have been described: Dinesh C.U., Reissig H.-U. Angew. Chem., Int. Ed. 38:1999;789-791.
15. Nandanan E., Dinesh C.U., Reissig H.-U. Tetrahedron. 56:2000;4267-4277.
16. 2 mediated cyclisations of unactivated olefinic ketones: see Ref. 5, and Beckwith A.L.J. Tetrahedron. 37:1981;3073-3100.
17. 2=0.1834.