Studies on the Deprotection of Triisopropylsilylarylacetylene Derivatives
Ismael Valois Escamilla, Luis Felipe Rangel Ramos, Javier Sánchez Escalera, and Alejandro Álvarez Hernández*
Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Hidalgo. Ciudad Universitaria, Carretera Pachuca–Tulancingo Km 4.5 s/n. Col. Carboneras Mineral de la Reforma, Hidalgo México 42184. México. alvarez@uaeh.edu.mx; alalvareher@yahoo.com
Received November 12, 2010.
Accepted February 1, 2011.
Abstract
Several conditions to deprotect triisopropylsilylarylacetylenes were examined. The triisopropylsilyl protecting group was efficiently removed under mild conditions with 1.5 equiv. of AgF in methanol, a protocol recently reported by Kim. A mixture of AgNO3/ KF gave lower yields. Other conditions using combinations of a transition metal, Cu(I), Co(II), Hg(II), and KF failed to react or produced decomposition. The AgF deprotection of TIPS–acetylenes allowed preparation of aryl and heteroaryl terminal alkynes.
Keywords: Desylylation, silver fluoride, alkyne protecting group, TIPS–acetylene.
Resumen
Se evaluaron diferentes métodos para remover el grupo protector en triisopropilarilacetilenos. Se logró remover el grupo protector bajo condiciones suaves usando el método de Kim: tratamiento del alquino protegido con 1.5 equiv. AgF en metanol. La mezcla AgNO3/KF funcionó dando menor rendimiento. Se estudiaron otras condiciones de desprotección en que se combinó un metal de transición Cu(I), Co(II), Hg(II) con KF pero ninguna de ellas funcionó. El tratamiento de un TIPS–alquino con AgF permitió preparar alquinos aromáticos y heteroaromáticos terminales.
Palabras clave: Desililación, fluoruro de plata, grupo protector de alquino, TIPS–acetileno.
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]]>Acknowledgements
Financial support from CONACYT (Project 2006–61247 and 2007–84453) is gratefully acknowledged. IVE and LFRR thank CONACYT for graduate scholarships.
References
1. Krüger, K.; Tillack, A.; Beller, M. Adv. Synth. Catal. 2008, 350, 2153–2167. [ Links ]
2. Bunz, U. H. F., Chem. Rev. 2000, 100, 1605–1644. [ Links ]
3. Wegner, G.; Müllen, K., Electronic Materials: The Oligomer Approach. Wiley–VCH, Ed. Weinheim, 1998. [ Links ]
4. Chinchilla, R.; Nájera, C. Chem. Rev. 2007, 107, 874–922. [ Links ]
5. Heravi, M. M.; Sadjadi, S. Tetrahedron 2009, 65, 7761–7775. [ Links ]
6. Plenio, H. Angew. Chem. Int. Ed. 2008, 47, 6954–6956. [ Links ]
7. Sonogashira, K. J. Organomet. Chem. 2002, 653, 46–49. [ Links ]
8. Sonogashira, K.; Tohda, Y.; Hagihara, N. Tetrahedron Lett. 1975, 4467–4470. [ Links ]
9. Doucet, H.; Hierso, J. C. Angew. Chem. Int. Ed. 2007, 46, 834–871. [ Links ]
10. Tykwinski, R. R. Angew. Chem. Int. Ed. 2003, 42, 1566–1568. [ Links ]
11. Jin, M. J.; Lee, D. H. Angew. Chem. Int. Ed. 2010, 49, 1119–1122. [ Links ]
12. Lipshutz, B. H.; Chung, D. W.; Rich, B. Org. Lett. 2008, 10, 3793–3796. [ Links ]
13. Trost, B. M. Angew. Chem. Int. Ed. 1995, 34, 259–281. [ Links ]
14. Trost, B. M. Acc. Chem. Res. 2002, 35, 695–705. [ Links ]
15. Kim, S.; Kim, S.; Lee, T.; Ko, H.; Kim, D. Org. Lett. 2004, 6, 3601–3604. [ Links ]
16. Kim, S.; Lee, Y. M.; Kang, H. R.; Cho, J.; Lee, T.; Kim, D. Org. Lett. 2007, 9, 2127–2130. [ Links ]
17. Marino, J. P.; Nguyen, H. N. J. Org. Chem. 2002, 67, 6841–6844. [ Links ]
18. Heuft, M. A.; Collins, S. K.; Yap, G. P. A.; Fallis, A. G. Org. Lett. 2001, 3, 2883–2886. [ Links ]
19. Csékei, M.; Novák, Z.; Kotschy, A. Tetrahedron 2008, 64, 975–982. [ Links ]
20. Melissaris, A. P.; Litt, M. H. J. Org. Chem. 1994, 59, 5818–5821. [ Links ]
21. Greene, T. W.; Wuts, P. G. M. Protective Groups in Organic Synthesis, Third Edition. John Wiley & Sons Inc, New York, 1999. [ Links ]
22. Wang, C.; Batsanov, A. S.; Bryce, M. R. J. Org. Chem. 2006, 71, 108–116. [ Links ]
23. Kim, S.; Kim, B.; In, J. Synthesis 2009, 1963–1968. [ Links ]
24. Moon, J.; Jeong, M.; Nam, H.; Ju, J.; Moon, J. H.; Jung, H. M.; Lee, S. Org. Lett. 2008, 10, 945–948. [ Links ]
25. Takahashi, S.; Kuroyama, Y.; Sonogashira, K.; Hagihara, N., Synthesis 1980, 627–630. [ Links ]
26. Richardson, C.; Reed, C. A. J. Org. Chem. 2007, 72, 4750–4755. [ Links ]
27. Ziessel, R.; Suffert, J.; Youinou, M. T. J. Org. Chem. 1996, 61, 6535–6546. [ Links ]
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