A New Protocol for Selective Deprotection of N-tert-Butoxycarbonyl Protective Group (t-Boc) with Sn(OTf)₂

References

• Greene , T.W. and Wuts , P.G.M. 1991 . Protective Groups in Organic Synthesis, , 2nd Ed. New York : John Wiley & Sons .
   Google Scholar
• Kocienski , P.J. 1994 . Protecting Groups Stuttgart : Georg Thieme Verlag .
   Google Scholar
• Schwyzer , R. , Costopanagiotis , A. and Sieber , P. 1963 . Helv. Chim. Acta , 46 : 870
   Google Scholar
• Sakai , N. and Ohfune , Y.J. 1992 . J. Am. Chem. Soc. , 114 : 998
   Web of Science ®Google Scholar
• Stahl , G.L. , Walter , R. and Smith , C.W. 1978 . J. Org. Chem. , 43 : 2285
   Web of Science ®Google Scholar
• Houghten , R.A. , Beckman , A. and Ostresh , J.M. 1986 . Int. J. Pept. Protein Res. , 27 : 653
   Google Scholar
• Yamashiro , D. , Blake , J. and Li , C.H. 1972 . J. Am. Chem. Soc. , 94 : 2855
   PubMed Web of Science ®Google Scholar
• Shaikh , N.S. , Gajare , A.S. , Deshpande , V.H. and Bedekar , A.V. 2000 . Tetrahedron Lett. , 41 : 385
   Web of Science ®Google Scholar
• Bose , D.S. and Lakshminarayana , V. 1999 . Synthesis , : 66
   Google Scholar
• Nigam , S.C. , Mann , A. , Taddei , M. and Wermuth , C.-G. 1989 . Synth. Commun. , 19 : 3139
   Google Scholar
• Hwu , J.R. , Jain , M.T. , Tsay , S.-Ch. and Hakimelahi , G.H. 1996 . Tetrahedron Lett. , 37 : 2035
   Web of Science ®Google Scholar
• Wei , Z.-Y. and Knaus , E.E. 1994 . Tetrahedron Lett. , 35 : 847
   Web of Science ®Google Scholar
• Boeckman , R.K. Jr. and Potenza , J.C. 1985 . Tetrahedron Lett. , 26 : 1411
   Web of Science ®Google Scholar
• Rawal , V.H. and Cava , M.P. 1985 . Tetrahedron Lett. , 26 : 6141
   Web of Science ®Google Scholar
• Thurston , D.E. and Bose , D.S. 1994 . Chem. Rev. , 94 : 433
   Web of Science ®Google Scholar
• Paquette , L.A. 1995 . Encyclopedia of Reagents for Organic Synthesis Vol. 7 , 4907 Chichester : John Wiley & Sons .
   Google Scholar
• Selected analytical data: compounds 1a, 1b, 1c, 1f isolated as amine hydrochloride salts. 1a: [α]D = −45.0° (c 0.53, CHCl3), 1H NMR (CDCl3) δ 1.45 (s, 9H), 1.85–2.05 (m. 4H), 3.38–3.60 (m, 2H), 3.75 (s, 3H), 4.16–4.36 (m, 1H). 1b: [α]D = −49.5° (c 3.4, CHCl3), 1H NMR (CDCl3) δ 1.45 (s, 9H), 1.50 (s, 9H), 1.81–1.98 (m, 3H), 2.15–2.30 (m, 2H), 3.38–3.58 (m, 2H), 4.10 (dd, 1H, J = 3.4, 8.9). Anal. calcd. for C14H26NO4: C, 61.7; H, 9.6; N, 5.1. Found: C, 61.5; H, 9.6; N, 5.2. 2a: m.p. 68–70°C (lit.[11] m.p. 69–71°C); [α]D = −31.0 (c 0.5, H2O), lit.[11] [α]D = −33 ± 2° (c 0.5, H2O). 2b: m.p. 108–109°C (lit.[13] m.p. 109–111°C); [α]D = −30.0 (c 1.2, EtOH), lit.[12] [α]D = −31.0° (c 2.0, EtOH), Anal. calcd. for C9H17NO: C, 69.6; H, 11.0; N, 9.0. Found: C, 69.0; H, 10.6; N, 8.7. 2c: m.p. 58–59°C (lit.[11] m.p. 57–60°C); 1d: [α]D = +13.5 (c 1.0, CHCl3). 1H NMR (CDCl3) δ 1.45 (s, 9H), 3.54–3.70 (m, 2H), 3.95–4.01 (m, 2H), 4.72–4.88 (bs, 1H), 5.12–5.31 (m, 2H), 5.75–5.94 (m, 1H), 7.22–7.35 (m, 5H). 2d: [α]D = + 24.5 (c 1.0, CHCl3). Anal. calcd. for C11H15NO;C, 74.5; H, 8.5; N, 7.9. Found: C, 75.0; H, 8.2; N, 7.5. 1f: [α]D = + 9.0° (c 1.0, CHCl3), 1H NMR (CDCl3): δ 1.44 (s, 9H), 1.50–1.81 (m, 6H), 3.11–3.27 (m, 2H), 3.75 (s, 3H), 4.18–4.31 (m, 1H), 4.78 (bs, 1H, exchangeable with D2O), 5.05 (bs, 1H), 5.08 (s, 2H), 7.22 (s, 5H). 2f: m.p. 116–118°C (lit. m.p. 117–118°C); Anal. calcd. for C15H22N2O4: C, 61.2; H, 7.5; N, 9.5. Found: C, 61.5; H, 7.8; N, 9.2. [α]D = +14.5° (c 1.0, H2O), lit. [α]D = +15.5° (c 2.0, H2O), Coggins, J.; Demayo, R.; Benoiton, N.L. Can. J. Chem. 1970, 48, 385. 1g: 1H NMR (CDCl3): δ 1.65 (s, 9H) 6.53 (d, 1H), 7.12–7.33 (m, 2H), 7.46–7. 48–57 (m, 2H), 8.10 (d, 1H). 2g: m.p. 53–55°C (lit.[11] m.p. 52–54°C)
   Google Scholar
• To dissolve the starting substrate CH2Cl2 can be replaced with any solvent, e.g., THF and CH3CN. During the reaction, carbon dioxide gas evolution was observed [positive Ba(OH)2 test]
   Google Scholar
• Aldrich Catalogue Handbook of Fine Chemicals 1999 – 2000 .
   Google Scholar
• Csandy , G. and Medzihradszky , K. 1988 . Org. Prep. Proced. Int. , 20 : 180
   Google Scholar