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Volumn , Issue 1, 2009, Pages 138-142

Oxidative alkylation of cyclic benzyl ethers with malonates and ketones using oxygen as the terminal oxidant

Author keywords

Copper; Cross coupling; Indium; Oxygen; Radical reactions

Indexed keywords


EID: 62349137371     PISSN: 09365214     EISSN: 14372096     Source Type: Journal    
DOI: 10.1055/s-0028-1087376     Document Type: Article
Times cited : (65)

References (50)
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    • 2nd ed, de Meijere, A, Diederich, F, Eds, Wiley-VCH: Weinheim
    • Metal-Catalyzed Cross-Coupling Reactions, 2nd ed.; de Meijere, A.; Diederich, F., Eds.; Wiley-VCH: Weinheim, 2004.
    • (2004) Metal-Catalyzed Cross-Coupling Reactions
  • 9
    • 4644355479 scopus 로고    scopus 로고
    • For examples of oxidative C-C bond-formation reactions using peroxides as the terminal oxidant, see: (a) Li, Z, Li, C.-J. J. Am. Chem. Soc. 2004, 126, 11810
    • For examples of oxidative C-C bond-formation reactions using peroxides as the terminal oxidant, see: (a) Li, Z.; Li, C.-J. J. Am. Chem. Soc. 2004, 126, 11810.
  • 23
    • 33645461780 scopus 로고    scopus 로고
    • For examples of oxidative C-C bond-formation reactions using DDQ as the terminal oxidant, see: (a) Zhang, Y, Li, C.-J. J. Am. Chem. Soc. 2006, 128, 4242
    • For examples of oxidative C-C bond-formation reactions using DDQ as the terminal oxidant, see: (a) Zhang, Y.; Li, C.-J. J. Am. Chem. Soc. 2006, 128, 4242.
  • 31
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    • For reviews on the use of NHPI as an effective catalyst for oxidation of C-H bonds in oxygen, see: a
    • For reviews on the use of NHPI as an effective catalyst for oxidation of C-H bonds in oxygen, see: (a) Ishii, Y.; Sakaguchi, S.; Iwahama, T. Adv. Synth. Catal. 2001, 343, 393.
    • (2001) Adv. Synth. Catal , vol.343 , pp. 393
    • Ishii, Y.1    Sakaguchi, S.2    Iwahama, T.3
  • 33
    • 33751154737 scopus 로고
    • For representative examples of NHPI as an effective catalyst for oxidation of C-H bonds in oxygen, see: a
    • For representative examples of NHPI as an effective catalyst for oxidation of C-H bonds in oxygen, see: (a) Ishii, Y.; Nakayama, K.; Takeno, M.; Sakaguchi, S.; Iwahama, T.; Nishiyama, Y. J. Org. Chem. 1995, 60, 3934.
    • (1995) J. Org. Chem , vol.60 , pp. 3934
    • Ishii, Y.1    Nakayama, K.2    Takeno, M.3    Sakaguchi, S.4    Iwahama, T.5    Nishiyama, Y.6
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    • 3.
    • 3.
  • 40
    • 62349134909 scopus 로고    scopus 로고
    • Representative Procedure and Spectroscopic Data, Synthesis of Dimethyl 2-(3,4-Dihydro-1H-isochromen-1-yl)malonate (3a) In a sealable test tube equipped with a magnetic stir bar was charged Cu(OTf) 2 (9.5 mg, 0.026 mmol, InCl3 (5.8 mg, 0.026 mmol, and NHPI (17.1 mg, 0.105 mmol, The reaction vessel was sealed and flushed with O2. The tube was attached to a balloon of O2 and charged with dimethyl malonate (1a, 0.060 mL, 0.524 mmol) and isochroman (2a, 0.33 mL, 2.6 mmol, The test tube was placed in an oil bath set at 55°C and was allowed to stir overnight. The reaction mixture was allowed to cooled to r.t. and the crude reaction mixture was purified by silica gel column chromatography (EtOAc-hexane, 1:4) to provide the desired alkylation product 3a (107.1 mg, 0.405 mmol, 77, as a clear colorless oil. 1H NMR (400 MHz, CDCl3, δ, 7.18-7.08 (m, 3 H, 6.99 d, J
    • 5b
  • 41
    • 62349116906 scopus 로고    scopus 로고
    • Representative Procedure and Spectroscopic Data, Synthesis of 2-(2,4-dihydro-1H-isochromen-1-yl)-1-phenylethanone (5a) In a sealable test tube equipped with a magnetic stir bar was charged Cu(OTf) 2 (9.0 mg, 0.025 mmol, InCl3 (5.5 mg, 0.025 mmol, and NHPI (16.3 mg, 0.100 mmol, The reaction vessel was sealed and flushed with O2. The tube was attached to a balloon of O2 and charged with acetophenone (4a, 0.058 mL, 0.500 mmol) and isochroman (2a, 0.31 mL, 2.5 mmol, The test tube was placed in an oil bath set at 75°C and was allowed to stir overnight. The reaction mixture was allowed to cooled to r.t, and the crude reaction mixture was purified by silica gel column chromatography (EtOAc-hexane, 1:5) to provide the desired alkylation product 5a (95.0 mg, 0.379 mmol, 75, as a pale yellow oil. 1H NMR (400 MHz, CDCl 3, δ, 8.03-8.00 (m, 2 H, 7.59-7.55 (m, 1 H, 7.49-7.45 m
    • 5a
  • 42
    • 62349116150 scopus 로고    scopus 로고
    • Previously, we proposed a similar intermediate for the oxidative arylation of cyclic benzyl amines with aryl boronic acids.6d
    • 6d
  • 43
    • 31444456960 scopus 로고    scopus 로고
    • Although alcohol 6 was not observed during the optimization process, we considered it to be a potential intermediate since benzylic alcohols are known to undergo alkylation with malonates and diketones in the presence of metal salts. For recent examples, see: (a) Yasuda, M, Somyo, T, Baba, A. Angew. Chem. Int. Ed. 2006, 45, 793
    • Although alcohol 6 was not observed during the optimization process, we considered it to be a potential intermediate since benzylic alcohols are known to undergo alkylation with malonates and diketones in the presence of metal salts. For recent examples, see: (a) Yasuda, M.; Somyo, T.; Baba, A. Angew. Chem. Int. Ed. 2006, 45, 793.
  • 48
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    • For the preparation of benzylic alcohol 6, see: Xu, Y. C.; Lebeau, E.; Gillard, J. W.; Attardo, G. Tetrahedron Lett. 1993, 34, 3841.
    • For the preparation of benzylic alcohol 6, see: Xu, Y. C.; Lebeau, E.; Gillard, J. W.; Attardo, G. Tetrahedron Lett. 1993, 34, 3841.
  • 49
    • 62349111959 scopus 로고    scopus 로고
    • Metal salts are known to reductively decompose alkyl hydroperoxides to its corresponding alkyloxy radical. Conversely, metal salts can be oxidized by hydroperoxides and generate hydroperoxide radicals.7
    • 7


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.