An unusual pathway to cyclobutane formation via desulfurative intramolecular photocycloaddition of an enone benzothiazoline pair

Organic Letters

Volumn 11, Issue 8, 2009, Pages 1685-1687

  Jo, Hyunil ^a   Fitzgerald, Mark E ^a,b   Winkler, Jeffrey D ^a  

^a UNIVERSITY OF PENNSYLVANIA   (United States)

^b BROAD INSTITUTE OF MIT AND HARVARD   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 65249153153     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol900186y     Document Type: Article

References (13)

1. For a recent review, see: Trost, B. M.: Jiang, C. Synthesis 2006, 36, 9-396.
2. Winkler. J. D.; Lee. E. C.-Y. J.Am. Chem. Soc. 2006, 128. 9040- 9041.
3. Larsen, D. S.: O'Shea, M. D. J. Chem. Soc, Perkin Trans. I. 1995, 1019-1028.
4. Hemdel, N. D.; Ko. C. C. H. J. Heterocycl. Chem. 1970. 7, 1007- 1011.
5. 2, 25 °C, 100% yield) gave 4,The structure and stereochemistry of 5 were confirmed by X-ray crystallographic analysis of the corresponding N-acetylated product, which was obtained on irradiation of 3 (R = Ac).The N-acetylated photosubstrate 3 was prepared from amine 7 by acetylation and subsequent NaOMe-mediated cyclization.Experimental details and spectral data are included in the Supporting Information.
6. For an example of photochemically mediated extrusion of sulfur from an episulfide. see: Puiatti, M.: Arguello. J.; Penonorv. A. Eur. J. Org. Chem. 2006, 4528-4536.
7. Exclusive formation of the bridged cyclobutane is an exception to the empirical "rule of five" as described by: Srinivasan, R.; Carlough, K. H. J. Am. Chem. Soc. 1967, 89, 4932-4936.
8. For an example of the observation of the crossed product as a minor component in a photochemical reaction, see: Basler, B.; Schuster. O.; Bach, T. J. Org. Chem. 2005, 70, 9798-9808.
9. Le Blanc, S.; Pete, J.-P.; Piva, O. Tetrahedron Lett. 1993, 34, 635-638.
10. For a clever example of a conformationally constrained system that leads to the selective formation of the crossed photoproduct. see: Crimmins, M.; Hauser, E. Org- Lett. 2000, 2, 281-284.
11. The preparation of 21 is based on the related work of: Fu, X.; Zhang, S.; Yin, J.; McAllister, T. L.: Jiang, S. A.: Tann, C.-H.: Thiruvengadam, T. K.; Zhang, F. Tetrahedron Lett. 2002, 43, 573-576.
12. Lee, E. C.-Y. Ph. D. Dissertation, University of Pennsylvania, Philadelphia, PA, 2007.
13. Vos. B. W.; Jenks, W. S. J.Am. Chem. Soc. 2002, 124, 2544- 2547.