Homogeneous debenzylation using extremely active catalysts: Tris(triflyl)methane, scandium(III) tris(triflyl)methide, and copper(II) tris(triflyl)methide

Synlett

Volumn , Issue 1, 2000, Pages 80-82

  Ishihara, Kazuaki ^a   Hiraiwa, Yukihiro ^a   Yamamoto, Hisashi ^a  

^a NAGOYA UNIVERSITY   (Japan)

Author keywords

Bronsted acids; Debenzylation; Homogeneous catalysis; Lewis acids; Scandium

Indexed keywords

ACID; ANISOLE; BENZYL DERIVATIVE; COPPER DERIVATIVE; METHANE; SCANDIUM;

ARTICLE; CATALYST; CHEMICAL REACTION; CHEMICAL STRUCTURE; CONTROLLED STUDY; SYNTHESIS;

EID: 0033958881     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: None     Document Type: Article

References (16)

1. Greene, T. W.; Wuts, P. G. M. Protective Groups in Organic Synthesis (Third Ed.), Wiley & Sons: New York, 1999.
2. Jobron, L.; Hindsgaul, O. J. Am. Chem. Soc. 1999, 121, 5835.
3. For a review of recent developments in deprotection of ester functional groups, see Salomon, C. S.; Mata, E. G.; Mascaretti, O. A. Tetrahedron 1993, 49, 3691.
4. Ishihara, K.; Kubota, M.; Yamamoto, H. Synlett 1996, 265.
5. Ishihara, K.; Karumi, Y.; Kubota, M.; Yamamoto, H. Synlett 1996, 839.
6. Ishihara, K.; Kubota, M.; Yamamoto, H. Synlett 1996, 1045.
7. acid values of tris(triflyl)methane, triflimide, and triflic acid, see Koppel, I. A.; Taft, R. W.; Anvia, F.; Zhu, S.-Z.; Hu, L.-Q.; Sung, K.-S.; DesMarteau, D. D.; Yagupolskii, L. M.; Yagupolskii, Y. L.; Ignat'ev, N. V.; Kondratenko, N. V.; Volkonskii, A. Y.; Vlasov, V. M.; Notario, R.; Maria, P.-C. J. Am. Chem. Soc. 1994, 116, 3047.
8. Waller, F. J.; Barrett, A. G. M.; Braddock, D. C.; Ramprasad, D.; McKinnell, R. M.; White, A. J. P.; Williams, D. J.; Ducray, R. J. Org. Chem. 1999, 64, 2910, and references therein.
9. Vij, A.; Zheng, Y. Y.; Kirchmeier, R. L.; Shreeve, J. M. Inorg. Chem. 1994, 33, 3281.
10. CF = 325 Hz) [internal standard: MeOH (49.0 ppm)].
11. Magnesium(II) triflimide was less active than scandium(III) triflimide for debenzylation of esters. cf. Grieco, P. A.; Handy, S. T. Tetrahedron Lett. 1997, 38, 2645.
12. Fukuzawa, S. In Lewis Acid Reagents Ed.; Yamamoto, H., Ed., Oxford University Press: Oxford 1999: chap. 11, pp. 185-201.
13. For our contribution concerning scandium(III) triflate, see a) Ishihara, K.; Kubota, M.; Kurihara, H.; Yamamoto, H. J. Am. Chem. Soc. 1995, 117, 4413, 6639 (corrections);
14. b) Ishihara, K.; Kubota, M,; Kurihara, H.; Yamamoto, H. J. Org. Chem. 1996, 61, 4560.
15. 5 (0 ppm)].
16. 4 and concentrated in vacuo to yield the crude product. Column chromatography of the crude product on silica gel gave a pure carboxylic acid. In the reaction of benzyl ethers and N-benzyl amides, pyridine (20 mL) was added to the reaction mixture. Column chromatography of the resultant mixture on silica gel (eluting first with hexane then with hexane-ethyl acetate) gave a pure debenzylation product.