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Synlett 2014; 25(20): 2908-2912
DOI: 10.1055/s-0034-1379478
letter
© Georg Thieme Verlag Stuttgart · New York

Cu(II)/TBAI-Catalyzed Esterification of Acid Hydrazides via C(sp3)–H Oxidative Coupling

Guifeng Liu*
a   Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry, Key Laboratory of Biomass Energy and Material of Jiangsu Province, Key and Open Laboratory on Forest Chemical Engineering, State Forestry Administration, National Engineering Laboratory for Biomass Chemical Utilization, Nanjing 210042, P. R. of China   Fax: +86(25)85482457   Email: liuguifeng067@163.com
b   Research Institute of New Technology, Chinese Academy of Forestry, Beijing 10091, P. R. of China
,
Can Jin
a   Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry, Key Laboratory of Biomass Energy and Material of Jiangsu Province, Key and Open Laboratory on Forest Chemical Engineering, State Forestry Administration, National Engineering Laboratory for Biomass Chemical Utilization, Nanjing 210042, P. R. of China   Fax: +86(25)85482457   Email: liuguifeng067@163.com
b   Research Institute of New Technology, Chinese Academy of Forestry, Beijing 10091, P. R. of China
,
Guomin Wu
a   Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry, Key Laboratory of Biomass Energy and Material of Jiangsu Province, Key and Open Laboratory on Forest Chemical Engineering, State Forestry Administration, National Engineering Laboratory for Biomass Chemical Utilization, Nanjing 210042, P. R. of China   Fax: +86(25)85482457   Email: liuguifeng067@163.com
b   Research Institute of New Technology, Chinese Academy of Forestry, Beijing 10091, P. R. of China
› Author Affiliations
Further Information

Publication History

Received: 20 August 2014

Accepted after revision: 22 September 2014

Publication Date:
17 October 2014 (online)

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Abstract

A Cu2+/TBAI-cocatalyzed allylic ester synthesis was developed, which allows a direct coupling of acid hydrazides and cycloalkanes. This process makes use of commercially available, inexpensive, and abundant starting materials. Based on the extensive experimental data, a plausible radical mechanism was suggested.

Key words

Cu2+/TBAI cocatalysis - direct coupling - acid hydrazides

Supporting Information

    for this article is available online at http://www.thieme-connect.com/products/ejournals/journal/ 10.1055/s-00000083.
  • Supporting Information
 

  • References and Notes

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  • 12 Synthesis of 3a–p A mixture of 1 (0.2 mmol), cycloalkane (2 mL), Cu(OAc)2 (10 mol%), TBAI (20 mol%), and TBHP (3 equiv) was stirred at 140 °C under N2 atmosphere for 36 h. The reaction mixture was washed with H2O and the aqueous phase was extracted with EtOAc (3×). The combined organic layer was washed with brine, dried over Na2SO4, and evaporated under reduced pressure. The crude product was purified by silica gel column chromatography to give the corresponding product. Compound 3a: yield 61%. 1H NMR (500 MHz, CDCl3): δ = 8.06 (d, J = 8.4 Hz, 2 H), 7.55 (m, 1 H), 7.42 (dd, J = 8.2, 7.0 Hz, 2 H), 6.01 (m, 1 H), 5.85 (m, 1 H), 5.51 (m, 1 H), 2.15 (m, 1 H), 2.04 (m, 1 H), 1.96 (m, 1 H), 1.84 (m, 1 H), 1.68 (m, 1 H). 13C NMR (125 MHz, CDCl3): δ = 166.2, 132.8, 132.7, 130.8, 129.5, 128.2, 125.7, 68.5, 28.4, 24.9, 18.9. HRMS: m/z calcd for C13H14O2 [M]+: 202.2491; found: 202.2488. Compound 3b: yield 70%. 1H NMR (500 MHz, CDCl3): δ = 8.00 (d, J = 9.0 Hz, 2 H), 6.90 (d, J = 9.0 Hz, 2 H), 5.96 (m, 1 H), 5.81 (m, 1 H), 5.45 (m, 1 H), 3.82 (s, 3 H), 2.04 (m, 3 H), 1.82 (m, 2 H), 1.67 (m, 1 H). 13C NMR (125 MHz, CDCl3): δ = 165.9, 163.2, 132.5, 131.5, 125.9, 123.2, 113.4, 68.2, 55.3, 28.4, 24.9, 18.9. HRMS: m/z calcd for C14H16O3 [M]+: 232.2750; found: 232.2755. Compound 3c: yield 58%. 1H NMR (500 MHz, CDCl3): δ = 7.70 (m, 2 H), 7.13 (m, 2 H), 5.80 (m, 1 H), 5.68 (m, 1 H), 5.35 (m, 1 H), 2.20 (m, 3 H), 1.99–1.65 (m, 6 H). 13C NMR (125 MHz, CDCl3): δ = 165.8, 137.5, 133.1, 132.2, 130.3, 129.6, 127.7, 126.4, 125.2, 68.0, 28.1, 24.6, 20.8, 18.6.. HRMS: m/z calcd for C14H16O3 [M]+: 232.2750; found: 232.2753 Compound 3d: yield 72%. 1H NMR (500 MHz, CDCl3): δ = 7.52 (dd, J = 8.4, 2.0 Hz, 1 H), 7.40 (d, J = 2.0 Hz, 1 H), 6.69 (m, 1 H), 5.83 (m, 1 H), 5.68 (m, 1 H), 5.28 (m, 1 H), 3.75 (s, 3 H), 3.70 (s, 3 H), 2.20–1.40 (m, 6 H). 13C NMR (125 MHz, CDCl3): δ = 165.4, 152.4, 148.1, 132.0, 125.5, 123.0, 122.8, 111.5, 109.7, 67.9, 55.4, 28.1, 24.5, 18.2. HRMS: m/z calcd for C15H18O4 [M]+: 262.3010; found: 262.3013. Compound 3e: yield 39%. 1H NMR (500 MHz, CDCl3): δ = 7.90 (d, J = 8.6 Hz, 2 H), 7.56 (d, J = 8.6 Hz, 2 H), 6.01 (m, 1 H), 5.832 (m, 1 H), 5.50 (m, 1 H), 2.05 (m, 3 H), 1.83 (m, 2 H), 1.70 (m, 1 H). 13C NMR (125 MHz, CDCl3): δ = 165.3, 132.8, 131.4, 130.99, 129.7, 127.67, 125.9, 68.8, 28.4, 24.8, 18.2.. HRMS: m/z calcd for C13H13BrO2 [M]+: 281.1451; found: 281.1450. Compound 3f: yield 30%. 1H NMR (500 MHz, CDCl3): δ = 8.28 (d, J = 8.8 Hz, 2 H), 8.22 (d, J = 8.8 Hz, 2 H), 6.05 (m, 1 H), 5.84 (m, 1 H), 5.55 (m, 1 H), 2.19–1.72 (m, 6 H). 13C NMR (125 MHz, CDCl3): δ = 164.0, 150.1, 135.9, 133.9, 130.4, 124.7, 123.2, 69.6, 28.0, 24.7, 18.6. HRMS: m/z calcd for C13H13NO4 [M]+: 247.2466; found: 247.2463. Compound 3g: yield 33%. 1H NMR (500 MHz, CDCl3): δ = 8.07 (m, 2 H), 7.10 (m, 2 H), 6.01 (m, 1 H), 5.82 (m, 1 H), 5.50 (m, 1 H), 2.06 (m, 3 H), 1.85 (m, 2 H), 1.70 (m, 1 H). 13C NMR (125 MHz, CDCl3): δ = 166.9, 165.2, 164.3, 132.9, 132.1, 132.0, 126.9, 125.5, 115.4, 115.2, 68.7, 28.3, 24.9, 18.9. HRMS: m/z calcd for C13H13FO2 [M]+: 220.2395; found: 220.2393. Compound 3h: yield 45%. 1H NMR (500 MHz, CDCl3): δ = 7.98 (d, J = 8.4 Hz, 2 H), 7.40 (d, J = 8.4 Hz, 2 H), 6.01 (m, 1 H), 5.82 (m, 1 H), 5.50 (m, 1 H), 2.05 (m, 3 H), 1.83 (m, 2 H), 1.70 (m, 1 H). 13C NMR (125 MHz, CDCl3): δ = 165.2, 139.0, 132.9, 130.9, 129.1, 128.5, 125.4, 68.8, 28.3, 24.8, 18.8. HRMS: m/z calcd for C13H13ClO2 [M]+: 236.6941; found: 236.6945. Compound 3i: yield 37%. 1H NMR (500 MHz, CDCl3): δ = 7.80 (m, 1 H), 7.53 (m, 1 H), 7.08 (m, 1 H), 6.00 (m, 1 H), 5.81 (m, 1 H), 5.47 (m, 1 H), 2.03 (m, 3 H), 1.84 (m, 2 H), 1.68 (m, 1 H). 13C NMR (125 MHz, CDCl3): δ = 161.8, 134.3, 133.1, 132.9, 132.0, 127.5, 125.4, 68.8, 28.2, 24.8, 18.8. HRMS: m/z calcd for C11H12SO2 [M]+: 208.2768; found: 208.2770. Compound 3j: yield 21%. 1H NMR (500 MHz, CDCl3): δ = 7.92 (m, 1 H), 7.64 (m, 1 H), 7.15 (m, 1 H), 6.21 (m, 1 H), 5.89 (m, 1 H), 5.67 (m, 1 H), 2.3 (m, 3 H), 1.88 (m, 2 H), 1.78 (m, 1 H). 13C NMR (125 MHz, CDCl3): δ = 162.5, 134.9, 134.1, 132.9, 132.0, 128.3, 125.9, 68.8, 28.5, 24.3, 18.1. HRMS: m/z calcd for C11H12O3 [M]+: 192.2112; found: 192.2110. Compound 3m: yield 65%. 1H NMR (500 MHz, CDCl3): δ = 8.02 (d, J = 8.4 Hz, 2 H), 7.53 (t, J = 7.2 Hz, 1 H), 7.40 (m, 2 H), 6.18 (m, 1 H), 5.92 (m, 2 H), 2.65 (m, 1 H), 2.33 (m, 2 H), 1.90 (m, 1 H). 13C NMR (125 MHz, CDCl3): δ = 166.6, 137.7, 132.7, 130.7, 129.5, 129.4, 128.2, 81.1, 31.2, 29.9. HRMS: m/z calcd for C12H12O2 [M]+: 288.2225; found: 188.2220. Compound 3n: yield 43%. 1H NMR (500 MHz, CDCl3): δ = 8.08 (m, 2 H), 7.57 (m, 1 H), 7.42 (m, 2 H), 5.91 (m, 1 H), 5.79 (m, 1 H), 5.66 (m, 1 H), 2.27 (m, 1 H), 2.14 (m, 1 H), 2.01 (m, 2 H), 1.90–1.66 (m, 3 H), 1.53–1.45 (m, 1 H). 13C NMR (125 MHz, CDCl3): δ = 166.1, 133.7, 133.0, 132.2, 130.9, 129.8, 128.5, 74.9, 33.1, 28.8, 26.9, 26.8. HRMS: m/z calcd for C14H16O2 [M]+: 216.2756; found: 216.2751. Compound 3o: yield 68%. 1H NMR (500 MHz, CDCl3): δ = 8.02 (d, J = 8.4 Hz, 2 H), 7.55 (t, J = 8.4 Hz, 1 H), 7.43 (t, J = 7.6 Hz, 2 H), 5.93 (m, 1 H), 5.72 (m, 1 H), 5.61 (m, 1 H), 2.33 (m, 1 H), 2.15 (m, 1 H), 2.04 (m, 1 H), 1.66 (m, 6 H), 1.42 (m, 1 H). 13C NMR (125 MHz, CDCl3): δ = 166.0, 132.7, 130.7, 130.7, 129.8, 129.5, 128.2, 73.0, 35.1, 28.8, 26.4, 25.9, 23.4. HRMS: m/z calcd for C15H18O2 [M]+: 230.3022; found: 230.3019.