Synlett 2021; 32(04): 383-386
DOI: 10.1055/s-0040-1707142
cluster
Radicals – by Young Chinese Organic Chemists
© Georg Thieme Verlag Stuttgart · New York

Radical-Hydroboration-Involved One-Pot Synthesis of Boron-Handled Glycol Derivatives

Bi-Yang Zhuang
,
Ji-Kang Jin
,
Feng-Lian Zhang
,
Yi-Feng Wang
This work was supported by the National Natural Science Foundation of China (Grant No. 21672195, 21702201, and 21971226).
Further Information

Publication History

Received: 17 April 2020

Accepted: 15 May 2020

Publication Date:
16 June 2020 (online)


Published as part of the Cluster Radicals – by Young Chinese Organic Chemists

Abstract

A one-pot two-step protocol for the direct synthesis of boron-handled glycol derivatives is reported. The procedure starts by an NHC–boryl-radical-promoted regioselective hydroboration of glycol-protected cinnamaldehydes. After that, the reaction mixture is treated with pinacol in the presence of HCl, leading to the direct formation of pinacol boronate handled glycol monoalkyl ethers. In this acid-triggered conversion, a reductive ring-opening of glycol-derived acetal moiety takes place, during which an NHC–borane unit serves as the hydride source.

Supporting Information

 
  • References and Notes

  • 1 Yue H, Zhao Y, Ma X, Gong J. Chem. Soc. Rev. 2012; 41: 4218
  • 2 Hall DG. Boronic Acids: Preparation and Applications in Organic Synthesis, Medicine and Materials, 2nd ed. Wiley-VCH; Weinheim: 2011
  • 4 Xu A.-Q, Zhang F.-L, Ye T, Yu Z.-X, Wang Y.-F. CCS Chem. 2019; 1: 504
    • 5a Ren S.-C, Zhang F.-L, Qi J, Huang Y.-S, Xu A.-Q, Yan H.-Y, Wang Y.-F. J. Am. Chem. Soc. 2017; 139: 6050
    • 5b Watanabe T, Hirose D, Curran DP, Taniguchi T. Chem. Eur. J. 2017; 23: 5404
    • 5c Shimoi M, Watanabe T, Maeda K, Curran DP, Taniguchi T. Angew. Chem. Int. Ed. 2018; 57: 9485
    • 5d Dai W, McFadden TR, Curran DP, Früchtl HA, Walton JC. J. Am. Chem. Soc. 2018; 140: 15868
    • 5e Dai W, Geib SJ, Curran DP. J. Am. Chem. Soc. 2019; 141: 12355
    • 5f Zhou N, Yuan X.-A, Zhao Y, Xie J, Zhu C. Angew. Chem. Int. Ed. 2018; 57: 3990
    • 5g Xia P.-J, Song D, Ye Z.-P, Hu Y.-Z, Xiao J.-A, Xiang H.-Y, Chen X.-Q, Yang H. Angew. Chem. Int. Ed. 2020; 59: 6706
    • 5h Xu W, Jiang H, Leng J, Ong H.-W, Wu J. Angew. Chem. Int. Ed. 2020; 59: 4009
    • 5i Qi J, Zhang F.-L, Huang Y.-S, Xu A.-Q, Ren S.-C, Yi Z.-Y, Wang Y.-F. Org. Lett. 2018; 20: 2360
    • 5j Jin J.-K, Zhang F.-L, Zhao Q, Lu J.-A, Wang Y.-F. Org. Lett. 2018; 20: 7558
    • 5k Qi J, Zhang F.-L, Jin J.-K, Zhao Q, Li B, Liu L.-X, Wang Y.-F. Angew. Chem. Int. Ed. 2020; 59 DOI: in press; 10.1002/anie.201915619.
  • 6 Ren S.-C, Zhang F.-L, Xu A.-Q, Yang Y, Zheng M, Zhou X, Fu Y, Wang Y.-F. Nat. Commun. 2019; 10: 1934
  • 7 Huang Y.-S, Wang J, Zheng W.-X, Zhang F.-L, Yu Y.-J, Zheng M, Zhou X, Wang Y.-F. Chem. Commun. 2019; 55: 11904
  • 8 Taniguchi T, Curran DP. Org. Lett. 2012; 14: 4540
    • 9a Pan X, Lacôte E, Lalevée J, Curran DP. J. Am. Chem. Soc. 2012; 134: 5669
    • 9b Dénès F, Pichowicz M, Povie G, Renaud P. Chem. Rev. 2014; 114: 2587
    • 10a Ueng S.-H, Makhlouf Brahmi M, Derat É, Fensterbank L, Lacôte E, Malacria M, Curran DP. J. Am. Chem. Soc. 2008; 130: 10082
    • 10b Ueng S.-H, Solovyev A, Yuan X, Geib SJ, Fensterbank L, Lacôte E, Malacria M, Newcomb M, Walton JC, Curran DP. J. Am. Chem. Soc. 2009; 131: 11256
  • 11 Bonet A, Odachowski M, Leonori D, Essafi S, Aggarwal VK. Nat. Chem. 2014; 6: 584
  • 12 General Procedure for the Preparation of Boron-Substituted Ethylene Glycol 3a A solution of 1a (95.7 mg, 0.422 mmol), NHC–BH3 (51.4 mg, 0.467 mmol), DTBP (30 μL, 0.163 mmol), and octadecanethiol (62 mg, 0.216 mmol) in toluene (5 mL) was stirred at 120 °C for 12 h under nitrogen atmosphere. After evaporation of solvent, the crude residue was treated with pinacol (77.5 mg, 0.655 mmol) and 2.0 M HCl (0.4 mL, 0.800 mmol) in THF (10 mL) for 2 h at room temperature. The reaction mixture was quenched with water and extracted with ethyl acetate. The organic layer was dried over Na2SO4 and concentrated in vacuo. The residue was purified by flash column chromatography (silica gel; petroleum ether–ethyl acetate = 3:1) to give product 3a (125.4 mg, 0.352 mmol) in 83% yield. Pale yellow liquid. 1H NMR (400 MHz, CDCl3): δ = 1.19 (6 H, s), 1.20 (6 H, s), 1.81 (1 H, dddd, J = 6.8, 6.8, 7.6, 8.0 Hz), 2.72 (1 H, br), 2.89 (1 H, dd, J = 7.6, 13.6 Hz), 3.00 (1 H, dd, J = 8.0, 13.6 Hz), 3.48–3.56 (4 H, m), 3.65–3.72 (2 H, m), 7.35–7.45 (3 H, m), 7.64 (1 H, s), 7.74–7.76 (2 H, m), 7.79 (1 H, dd, J = 1.6, 6.0 Hz). 13C NMR (100 MHz, CDCl3): δ = 24.6, 24.7, 33.5, 61.5, 71.2, 71.6, 83.4, 125.0, 125.8, 126.9, 127.3, 127.5, 127.6, 127.7, 131.9, 133.4, 139.0. 11B NMR (128.4 MHz, CDCl3): δ = 33.7 (1 B, s). ESI-HRMS: m/z calcd for C21H29 11BNaO4 [M + Na]+: 379.2057; found: 379.2065.