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Organic Letters
Volumn 11, Issue 13, 2009, Pages 2752-2755
Chemoselective chemical and electrochemical deprotections of aromatic esters
Author keywords

[No Author keywords available]
Indexed keywords

ALCOHOL DERIVATIVE; AROMATIC HYDROCARBON; ESTER;
EID: 67649491253     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol900828x     Document Type: Article
Times cited : (36)
References (18)
  • 1
    • 0003405157 scopus 로고    scopus 로고
    • 3rd ed, Georg Thieme Verlag: New-York
    • (a) Kocienski, P. J. Protecting Groups, 3rd ed.; Georg Thieme Verlag: New-York, 2005.
    • (2005) Protecting Groups
    • Kocienski, P.J.1
  • 13
    • 67649470666 scopus 로고    scopus 로고
    • Standard reduction procedure: In a 100 mL flame-dried three necked flask, maintained under argon and equipped with a condenser and a magnetic stirrer, 2.3 mL (13.4 mmol, 20 equiv) of HMPA are added to 33.5 mL (3.4 mmol, 5 equiv) of SmI2 (0.1 M in THF, The solution turns immediately into a purple color. Finally, 0.55 mL of methanol (13.4 mmol, 20 equiv) are added. The solution is then heated at reflux and 210 mg (0.67 mmol, 1 equiv) of the 9-fluorenylmethyl toluate, dissolved in a minimum of THF, is quickly added. The reaction is followed by TLC the reaction is usually finished within 5 seconds to 1 minute, After completion, the mixture is quenched by the addition of 10 mL of saturated aqueous NH4CI. The aqueous layer is extracted three times with 10 mL of dichloromethane and the organic phases are pooled, washed twice with a saturated solution of sodium carbonate and then dried over anhydrous sodium sulfate. The solvent is removed under reduced pressure and the crude product is puri
    • f = 0.4). The title compound is obtained as a white powder in 99% yield. This material proved to be identical to an authentic sample of fluorenemethanol.
  • 17
    • 67649500082 scopus 로고    scopus 로고
    • Standard constant current electrolysis procedure: An H-type cell, with two compartments of 100 mL, separated by a sintered glass with a porosity of 40 μm, was dried during one night at 200 0C. Then, each cell was equipped with a graphite electrode of 6 cm2 and a magnetic stirring bar. Both compartments were then flushed with argon during 10 minutes. After filling them with 5 g Of NBu4BF4 and with 100 mL of a mixture of NMP/iPrOH (93:7, 210 mg (0.668 mmol) of fluorenylmethyl toluate 6, dissolved in a little NMP, were added to the cathodic compartment and the solution was heated to 90 0C. Then, the intensity of the current was fixed at 90 mA and the mixture was electrolysed until completion of the reaction, as shown by TLC or by GC. The cell was then cooled to room temperature and the catholyte was carefully diluted with. 100 mL of 4N HCl. The resulting solution was extracted 4 times with. 30 mL of ether. The organic phases were pooled, dried o
    • f = 0.4), affording the title compound as a white powder in 81% yield. This material proved to be identical to an authentic sample of fluorenemethanol.
  • 18
    • 67649496440 scopus 로고    scopus 로고
    • Standard fixed potential electrolysis procedure: An H-type cell, with two compartments of 100 mL, separated by a sintered glass with a porosity of 40 μm, was dried during one night at 200 0C. Then, each cell was equipped with a graphite electrode of 6 cm2 and a magnetic stirring bar. Both compartments were then flushed with argon during 10 minutes. After filling them with 5 g of NBu4BF4 and with 100 mL of a mixture of NMP/ iPrOH (93:7, a reference electrode (Ag/AgCl saturated with LiCl in. EtOH) was introduced through a salt bridge containing the solvent and the supporting electrolyte. Then 200 mg (0.5 mmol) of the diester 26, dissolved in a little NMP, were added to the cathodic compartment and the solution was stirred and heated to 90 0C. The intensity of the potential was fixed at -2.0 V and the mixture was electrolysed until completion of the reaction, as indicated by TLC, GC and the drop of the current. The cell was then, cooled t
    • f = 0.3), affording the title compound as a thick oil in 80% yield.

* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.