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Synlett
Volumn , Issue 13, 2008, Pages 1977-1980
Mild debenzylation of aryl benzyl ether with BCl3 in the presence of pentamethylbenzene as a non-lewis-basic cation scavenger
Author keywords

Aryl benzyl ethers; Debenzylation; Phenols; Protecting groups; Total synthesis
Indexed keywords

ANTIBIOTIC AGENT; BENZENE DERIVATIVE; BENZYL ETHER; BORON TRICHLORIDE; CHLORIDE; ETHER; LEWIS BASE; PENTAMETHYLBENZENE; YATAKEMYCIN;
EID: 49649111005     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/S-2008-1077980     Document Type: Article
Times cited : (81)
References (12)
  • 6
    • 84998217257 scopus 로고
    • treatment of O-benzyltyrosine with TFA yielded tyrosine and undesired 3-benzyltyrosine in the ratio of 57:43
    • (a) Kiso, Y.; Isawa, H.; Kitagawa, K.; Akita, T. Chem. Pharm. Bull. 1978, 26, 2562; treatment of O-benzyltyrosine with TFA yielded tyrosine and undesired 3-benzyltyrosine in the ratio of 57:43.
    • (1978) Chem. Pharm. Bull , vol.26 , pp. 2562
    • Kiso, Y.1    Isawa, H.2    Kitagawa, K.3    Akita, T.4
  • 7
    • 85008004893 scopus 로고
    • a combination of thioanisole with TFA was effective to debenzylation of O-benzyltyrosine without formation of 3-benzyltyrosine
    • (b) Kiso, Y.; Ukawa, K.; Nakamura, S.; Ito, K.; Akita, T. Chem. Pharm. Bull. 1980, 28, 673; a combination of thioanisole with TFA was effective to debenzylation of O-benzyltyrosine without formation of 3-benzyltyrosine.
    • (1980) Chem. Pharm. Bull , vol.28 , pp. 673
    • Kiso, Y.1    Ukawa, K.2    Nakamura, S.3    Ito, K.4    Akita, T.5
  • 8
    • 0011221105 scopus 로고    scopus 로고
    • Various cation scavengers on debenzylation of O-benzyltyrosine in TFA were investigated. It was reported that pentamethylbenzene increased the rate of deprotection most efficiently among other scavengers such as thioanisole, anisole, 1,3-dimethoxybenzene, 1,2,3-dimethoxybenzene, m-xylene, 1,2,3-trimethylbenzene, and 1,2,3,4-tetramethylbenzene. Isolation and characterization of benzylpentamethy lbenzene generated by trapping of benzyl cation were also reported. See: Yoshino, H.; Tsuchiya, Y.; Saito, I.; Tsujii, M. Chem. Pharm. Bull. 1987, 35, 3438.
    • (a) Various cation scavengers on debenzylation of O-benzyltyrosine in TFA were investigated. It was reported that pentamethylbenzene increased the rate of deprotection most efficiently among other scavengers such as thioanisole, anisole, 1,3-dimethoxybenzene, 1,2,3-dimethoxybenzene, m-xylene, 1,2,3-trimethylbenzene, and 1,2,3,4-tetramethylbenzene. Isolation and characterization of benzylpentamethy lbenzene generated by trapping of benzyl cation were also reported. See: Yoshino, H.; Tsuchiya, Y.; Saito, I.; Tsujii, M. Chem. Pharm. Bull. 1987, 35, 3438.
  • 11
    • 49649092100 scopus 로고    scopus 로고
    • +]: 244.1099; found: 244.1089.
    • +]: 244.1099; found: 244.1089.
  • 12
    • 49649125202 scopus 로고    scopus 로고
    • Boron trichloride (1.0 M in CH2Cl2) was purchased from Aldrich Chemical Company and was used as supplied. Pentamethylbenzene was purchased from Tokyo Chemical Industry Co, Ltd. and was used as supplied. Typical Procedure (Table 3, Entry 20) To a stirred solution of 7V-[3-(benzyloxy)phenyl]-2,2,2-trifluoroethanamide (1.61 g, 5.44 mmol, 1.0 equiv) and pentamethylbenzene (2.42 g, 16.3 mmol, 3.0 equiv) in dry CH 2Cl2 (27.0 mL) was added BCl3 (1.0 M in CH 2Cl2, 10.9 mL, 2.0 equiv) dropwise over 10 min via syringe at -78 °C. After 15 min, TLC indicated complete consumption of the starting material. The reaction was quenched with CHCl3-MeOH (10:1, 20 mL) at -78 °C, and the resulting mixture was warmed to r.t. The excess organic solvents were removed under reduced pressure. The residue was purified by column chromatography on SiO2 eluent: hexanes to hexanes-EtOAc =1:1, gradient
    • +]: 206.0429; found: 206.0427.

* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.