메뉴 건너뛰기




Volumn 73, Issue 2, 2008, Pages 364-368

Highly efficient photochemically induced thiyl radical-mediated racemization of aliphatic amines at 30 °C

Author keywords

[No Author keywords available]

Indexed keywords

ALIPHATIC AMINES; TERTIARY AMINES;

EID: 40949160930     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo702241y     Document Type: Article
Times cited : (37)

References (50)
  • 7
  • 16
    • 33846964661 scopus 로고    scopus 로고
    • Paquette, L. A, Crich, D, Fuchs, P, Molander, G, Eds, Wiley: Chichester, DOI:10.1002/047084289X.m00633
    • Feray, L.; Bertrand, M. In e-Encyclopedia of Reagents for Organic Synthesis; Paquette, L. A., Crich, D., Fuchs, P., Molander, G., Eds.; Wiley: Chichester, 2005; DOI:10.1002/047084289X.m00633.
    • (2005) e-Encyclopedia of Reagents for Organic Synthesis
    • Feray, L.1    Bertrand, M.2
  • 17
    • 41149179639 scopus 로고    scopus 로고
    • 1H NMR spectrum of the crude mixture showed that amine was degraded. The residual amine was difficult to quantify with respect to the internal standard owing to the complexity of the mixture.
    • 1H NMR spectrum of the crude mixture showed that amine was degraded. The residual amine was difficult to quantify with respect to the internal standard owing to the complexity of the mixture.
  • 18
    • 41149115170 scopus 로고
    • For the photoinitiated cyclization of thiyl radicals, see: a, Abramovitch, R. A, Ed, Plenum: New York, Chapter 3, pp, and references cited therein
    • For the photoinitiated cyclization of thiyl radicals, see: (a) Surzur, J.-M. In Reactive Intermediates; Abramovitch, R. A., Ed.; Plenum: New York, 1981; Vol. 2, Chapter 3, pp 177-186 and references cited therein.
    • (1981) Reactive Intermediates , vol.2 , pp. 177-186
    • Surzur, J.-M.1
  • 20
    • 41149147632 scopus 로고    scopus 로고
    • Spectral distribution ranges from 250 to 350 nm with maximum intensity of irradiance at 300 nm
    • Spectral distribution ranges from 250 to 350 nm with maximum intensity of irradiance at 300 nm.
  • 21
    • 41149143192 scopus 로고    scopus 로고
    • In the presence of methyl thioglycolate, amine 1 racemization reached completion in 5 h in a Pyrex vessel. The final ee was only 45% in the presence of cyclohexane thiol under the same experimental conditions
    • In the presence of methyl thioglycolate, amine 1 racemization reached completion in 5 h in a Pyrex vessel. The final ee was only 45% in the presence of cyclohexane thiol under the same experimental conditions.
  • 22
    • 41149178684 scopus 로고    scopus 로고
    • Calculated S-H bond dissociation energies at 298 K according to the G3B3(MP2) level of theory are 359.9 and 364.4 kJ/mol for n-BuSH and HSCH2CO2Me, respectively; see ref 2
    • 2Me, respectively; see ref 2.
  • 23
    • 10844241549 scopus 로고    scopus 로고
    • The electron affinities of thiyl radicals were shown to give linear correlation with S-H BDEs and with proton affinities; see: (a) Fattahi, A, Kass, S. R. J. Org. Chem. 2004, 69, 9176-9183
    • The electron affinities of thiyl radicals were shown to give linear correlation with S-H BDEs and with proton affinities; see: (a) Fattahi, A.; Kass, S. R. J. Org. Chem. 2004, 69, 9176-9183.
  • 25
    • 18744394619 scopus 로고    scopus 로고
    • The oxidation potentials of primary, secondary, and tertiary amines have been calculated by Fu et al.; see: (a) Fu, Y.; Liu, L.; Yu, H.-Z.; Wang, Y.-M.; Guo, Q.-X. J. Am. Chem. Soc. 2005, 127, 7227-7234. The calculated IP determined in acetonitrile for n-propylamine, di-n-propylamine, and tri-n-propylamine at the B3LYP/6311++G(2df,2p)//B3LYP/6-31G(d) level of theory, using the PCM solvation model, are 8.81, 8.03, and 7.38 eV, respectively. The corresponding E° vs NHE values are 1.63, 1.43, and 1.02 eV. The values are very close to experimental ones.
    • The oxidation potentials of primary, secondary, and tertiary amines have been calculated by Fu et al.; see: (a) Fu, Y.; Liu, L.; Yu, H.-Z.; Wang, Y.-M.; Guo, Q.-X. J. Am. Chem. Soc. 2005, 127, 7227-7234. The calculated IP determined in acetonitrile for n-propylamine, di-n-propylamine, and tri-n-propylamine at the B3LYP/6311++G(2df,2p)//B3LYP/6-31G(d) level of theory, using the PCM solvation model, are 8.81, 8.03, and 7.38 eV, respectively. The corresponding E° vs NHE values are 1.63, 1.43, and 1.02 eV. The values are very close to experimental ones.
  • 26
    • 0033398685 scopus 로고    scopus 로고
    • For a quantitative approach to IE and gas-phase basicity, see: b
    • For a quantitative approach to IE and gas-phase basicity, see: (b) Cherkasov, A. R.; Jonsson, M.; Galkin, V. J. Mol. Graphics Mod. 1999, 17, 28-42.
    • (1999) J. Mol. Graphics Mod , vol.17 , pp. 28-42
    • Cherkasov, A.R.1    Jonsson, M.2    Galkin, V.3
  • 32
    • 41149155949 scopus 로고    scopus 로고
    • For the influence of amine class on the catalysis by aliphatic thiols of the photoreduction of triplets carbonyls, see: (a) Stone, P. G, Cohen, S. J. Am. Chem. Soc. 1980, 102, 5686-5688
    • For the influence of amine class on the catalysis by aliphatic thiols of the photoreduction of triplets carbonyls, see: (a) Stone, P. G.; Cohen, S. J. Am. Chem. Soc. 1980, 102, 5686-5688.
  • 35
    • 33644657172 scopus 로고    scopus 로고
    • a values in water are 10.69 for n-propylamine, 11.09 for diethylamine, and 11.09 for triethylamine; see: (a) Lu, G.; Grossman, J. E.; Lambert, J. B. J. Org. Chem. 2006, 71, 1769-1776.
    • a values in water are 10.69 for n-propylamine, 11.09 for diethylamine, and 11.09 for triethylamine; see: (a) Lu, G.; Grossman, J. E.; Lambert, J. B. J. Org. Chem. 2006, 71, 1769-1776.
  • 36
    • 33750614288 scopus 로고    scopus 로고
    • a values in acetonitrile are 18.4 for ethylamine, 18.8 for diethylamine, and 18.5 for triethylamine; see: (b) Li, J.-N.; Fu, Y.; Liu, L. Guo, Q.-X. Tetrahedron 2006, 62, 11801-11813.
    • a values in acetonitrile are 18.4 for ethylamine, 18.8 for diethylamine, and 18.5 for triethylamine; see: (b) Li, J.-N.; Fu, Y.; Liu, L. Guo, Q.-X. Tetrahedron 2006, 62, 11801-11813.
  • 37
    • 0000891655 scopus 로고
    • Solvent effect on amine basicity is well known. A subtle differentiation, according to the nature of the alkyl substituent, might be induced by a solvent of low dielectric constant like benzene. See: c
    • Solvent effect on amine basicity is well known. A subtle differentiation, according to the nature of the alkyl substituent, might be induced by a solvent of low dielectric constant like benzene. See: (c) Headley, A. D. J. Org. Chem. 1991, 56, 3688-3691.
    • (1991) J. Org. Chem , vol.56 , pp. 3688-3691
    • Headley, A.D.1
  • 40
    • 41149120000 scopus 로고    scopus 로고
    • a value for n-BuSH is 10.9; see: McMillen, D. F.; Golden, D. M. Annu. Rev. Phvs. Chem. 1982, 33, 493-532.
    • a value for n-BuSH is 10.9; see: McMillen, D. F.; Golden, D. M. Annu. Rev. Phvs. Chem. 1982, 33, 493-532.
  • 41
    • 0035840982 scopus 로고    scopus 로고
    • For other photoinduced electron transfer processes involving amines, see: a
    • For other photoinduced electron transfer processes involving amines, see: (a) Pischel, U.; Nau, W. M. J. Am. Chem. Soc. 2001, 123, 9727-9737.
    • (2001) J. Am. Chem. Soc , vol.123 , pp. 9727-9737
    • Pischel, U.1    Nau, W.M.2
  • 44
    • 0004081209 scopus 로고    scopus 로고
    • For general reviews, see: a, Alfassi, Z. B, Ed, Wiley: Chichester, Chapter 5
    • For general reviews, see: (a) Asmus, K.-D.; Bonifačić, M. In S-Centered Radicals; Alfassi, Z. B., Ed.; Wiley: Chichester, 1999; Chapter 5.
    • (1999) S-Centered Radicals
    • Asmus, K.-D.1    Bonifačić, M.2
  • 46
    • 0005980951 scopus 로고
    • For EPR studies of photoreaction of aliphatic thiols leading to disulfide radical anions, see
    • (c) For EPR studies of photoreaction of aliphatic thiols leading to disulfide radical anions, see: Cremonini, M. A.; Lunazzi, L. Placicci, G. J. Org. Chem. 1993, 58, 3805-3810.
    • (1993) J. Org. Chem , vol.58 , pp. 3805-3810
    • Cremonini, M.A.1    Lunazzi, L.2    Placicci, G.3
  • 48
    • 41149168717 scopus 로고    scopus 로고
    • For the theoretical prediction of the absolute standard redox potentials of a series of α-amino radicals, see ref 13. The values calculated in solution in acetonitrile, at the B3LYP/6-311++G-(2df,2p)//B3LYP/6- 31G(d) level of theory using the PCM solvation model, range from -1.5 V to 0.36 V (E°, 0.66 V for H2NCH2•; -1.47 V for (Me)2NCH2•
    • •).
  • 50
    • 41149086260 scopus 로고    scopus 로고
    • Only methyl thioglycolate enabled the monitoring of the reaction by 1H NMR while irradiating in C6D6 in the presence of pentamethylbenzene as internal standard. The signals of the methylene protons and of the methoxy group in both compounds are distinct from each other. The δ values for the methoxy group and the methylene protons are 3.20 and 2.66, respectively, in methyl thioglycolate. The δ values for the methoxy group and the methylene protons are 3.25 and 3.17, respectively, in the corresponding disulfide. It can be noted that the methylene signal in methyl thioglycolate remains a doublet (J, 8.1 Hz) in the presence of amine 3, but due to a fast exchange of the SH proton, no coupling is observed in the presence of amine 1 and the other amines in the series. This confirms the low basicity of amine 3
    • 6 in the presence of pentamethylbenzene as internal standard. The signals of the methylene protons and of the methoxy group in both compounds are distinct from each other. The δ values for the methoxy group and the methylene protons are 3.20 and 2.66, respectively, in methyl thioglycolate. The δ values for the methoxy group and the methylene protons are 3.25 and 3.17, respectively, in the corresponding disulfide. It can be noted that the methylene signal in methyl thioglycolate remains a doublet (J = 8.1 Hz) in the presence of amine 3, but due to a fast exchange of the SH proton, no coupling is observed in the presence of amine 1 and the other amines in the series. This confirms the low basicity of amine 3.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.