A samarium(II)-mediated, stereoselective cyclization for the synthesis of azaspirocycles

Organic Letters

Volumn 10, Issue 19, 2008, Pages 4291-4294

  Guazzelli, Giuditta ^a   Duffy, Lorna A ^a   Procter, David J ^a  

^a UNIVERSITY OF MANCHESTER   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 61349176409     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol8017209     Document Type: Article

References (31)

1. For recent reviews on the use of samarium(II) iodide: (a) Molander, G. A.; Harris, C. R. Tetrahedron 1998, 54, 3321.
2. (b) Kagan, H.; Namy, J. L. In Lanthanides: Chemistry and Use in Organic Synthesis; Kobayashi, S., Ed.; Springer: Berlin, 1999; p 155.
3. (c) Steel, P. G. J. Chem. Soc., Perkin Trans. 1 2001, 2727.
4. (d) Kagan, H. B. Tetrahedron 2003, 59, 10351.
5. (e) Dahlén, A.; Hilmersson, G. Eur. J. Inorg. Chem. 2004, 3393.
6. (f) Edmonds, D. J.; Johnston, D.; Procter, D. J. Chem. Rev. 2004, 104, 3371.
7. (a) Johnston, D.; McCusker, C. M.; Procter, D. J. Tetrahedron Lett. 1999, 40, 4913.
8. (b) Johnston, D.; McCusker, C. F.; Muir, K.; Procter, D. J. J. Chem. Soc., Perkin Trans. 1 2000, 681.
9. (c) Johnston, D.; Francon, N.; Edmonds, D. J.; Procter, D. J. Org. Lett. 2001, 3, 2001.
10. (d) Johnston, D.; Couché, E.; Edmonds, D. J.; Muir, K.; Procter, D. J. Org. Biomol. Chem. 2003, 328.
11. (e) Edmonds, D. J.; Muir, K. W.; Procter, D. J. J. Org. Chem. 2003, 68, 3190.
12. (a) Mutton, T. K.; Muir, K.; Procter, D. J. Org. Lett. 2002, 4, 2345.
13. (b) Hutton, T. K.; Muir, K.; Procter, D. J. Org. Lett. 2003, 5, 4811.
14. Sloan, L. A.; Baker, T. M.; Macdonald, S. J. F.; Procter, D. J. Synlett 2007, 3155.
15. (a) Ma, Z.; Chu, D. T. W.; Cooper, C. S.; Li, Q.; Fung, A. K. L.; Wang, S.; Shen, L. L.; Flamm, R. K.; Nilius, A. M.; Alder, J. D.; Meulbroek, J. A.; Sun Or, Y. J. Med. Chem. 1999, 42, 4202.
16. (b) Makovec, F.; Peris, W.; Revel, L.; Giovanetti, R.; Mennuni, L.; Rovati, L. C. J. Med. Chem. 1992, 35, 28.
17. (c) Obniska, J.; Kaminski, K.; Zagorska, A.; Dzierzawska-Majewska, A.; Karolak-Wojciechowska, J. J. Fluorine Chem. 2006, 127, 417.
18. (d) Yang, L.; Morriello, G.; Prendergast, K.; Cheng, K.; Jacks, T.; Chan, W. W.-S.; Schleim, K. D.; Smith, R. G.; Patchett, A. A. Biorg. Med. Chem. Lett. 1998, 8, 107.
19. N-Aryl lactams that were not commercially available were prepared by the N-arylation of lactams according to the procedure of Buchwald: Klapars, A.; Huang, X.; Buchwald, S. L. J. Am. Chem. Soc. 2002, 124, 7421.
20. (a) Jackson, J. A.; Hammond, G. B.; Wiemer, D. F. J. Org. Chem. 1989, 54, 4750.
21. (b) Lee, K.; Jackson, J. A.; Wiemer, D. F. J. Org. Chem. 1993, 58, 5967.
22. (c) Yu, J. S.; Weimer, D. F. J. Org. Chem. 2007, 72, 6263.
23. See Supporting Information for the synthesis of lactams and lactam phosphonates.
24. We have shown that the double-bond stereochemistry has no bearing on the yield or stereochemical outcome of the reductive-aldol cyclization. See ref 3b.
25. See Supporting Information for CCDC numbers and X-ray crystal-lographic data.
26. 2, see: Chopade, P. R.; Prasad, E.; Flowers, R. A., II. J. Am. Chem. Soc. 2004, 126, 44.
27. Alternatively, reduction to a dianion intermediate may occur prior to protonation and aldol reaction.
28. For a review on the chemistry of samarium enolates, see: Rudkin, I. M.; Miller, L. C.; Procter, D. J. Organomet. Chem. 2008, 34, 19.
29. We have reported that the use of t-BuOH as a cosolvent in the cyclizations of lactone substrates, such as 1, results in a switch in reaction course, and cyclobutanols are obtained diastereoselectively (see ref 3b). For analogous lactam substrates, the use of t-BuOH as a cosolvent results in mixtures of acyclic reduction products, spirocyclopentanols, and cyclobutanols.
30. 2 reductions, see: Duffy, L. A.; Matsubara, H.; Procter, D. J. J. Am. Chem. Soc. 2008, 130, 1136.
31. De Lamo Marin, S.; Martens, T.; Mioskowski, C.; Royer, J. J. Org. Chem. 2005, 70, 10592. Attempts to remove the N-PMP group in 9g using ceric(IV) ammonium nitrate gave low isolated yields (20-30%) of 17g.