Metal-free Reduction of Nitro Aromatics to Amines with B₂(OH)₄/H₂O

Abstract

A metal-free reduction of nitro aromatics mediated by di­boronic acid with water as both the hydrogen donor and solvent under mild conditions has been developed. A series of aromatic amines were obtained with good functional group tolerance and in good yields.

Key words

diboronic acid - nitro aromatics - amines - reduction - water

• References and Notes

• 1a Downing RS. Kunkeler PJ. Bekkum HV. Catal. Today 1997; 37: 121
• 1b Ono N. Synthesis 2001; 2528
• 1c Gunanathan C. Milstein D. Angew. Chem. Int. Ed. 2008; 47: 8661
• 1d Kantam ML. Chakravarti R. Pal U. Sreedhar B. Bhargava S. Adv. Synth. Catal. 2008; 350: 822
• 1e Liu S. Wang Y. Jiang J. Jin Z. Green Chem. 2009; 11: 1397
• 1f Birch AM. Groombridge S. Law R. Leach AG. Mee CD. Schramm CJ. J. Med. Chem. 2012; 55: 3923
• 1g Vishnoi S. Agrawal V. Kasana VK. J. Agric. Food. Chem. 2009; 57: 3261
• 1h Tafesh AM. Weiguny J. Chem. Rev. 1996; 96: 2035
• 1i Pandarus V. Ciriminna R. Béland F. Pagliaro M. Adv. Synth. Catal. 2011; 353: 1306
• 1j Mikami Y. Noujima A. Mitsudome T. Mizugaki T. Jitsukawa K. Kaneda K. Chem. Lett. 2010; 39: 223
• 1k Cárdenas-Lizana F. Gómez-Quero S. Keane MA. Catal. Commun. 2008; 9: 475
• 2a Tsukinoki T. Tsuzuki H. Green. Chem. 2001; 3: 37
• 2b Sreedhar B. Devi DK. Yada D. Catal. Commun. 2011; 12: 1009
• 2c Mohan V. Pramod CV. Suresh M. Reddy KH. P. Raju BD. Rao KS. R. Catal. Commun. 2012; 18: 89
• 3 Béchamp A. Ann. Chim. Phys. 1854; 42: 186

For a review on the advancement of methodologies for reduction of nitro aromatics, see:
• 4a Kadam HK. Tilve SG. RSC Adv. 2015; 5: 83391 , and references cited therein
• 4b Blaser HU. Steiner H. Studer M. ChemCatChem. 2009; 1: 210
• 4c Pietrowski M. Curr. Org. Synth. 2012; 9: 470
• 4d Orlandi M. Brenna D. Harms R. Jost S. Benaglia M. Org. Process Res. Dev. 2016; 22: 430
• 5 Bae JW. Cho YJ. Lee SH. Yoon CO. M. Yoon CM. Chem. Commun. 2000; 1857
• 6 Lu H. Geng Z. Li J. Zou D. Wu Y. Wu Y. Org. Lett. 2016; 18: 2774
• 7 Cummings SP. Le TN. Fernandez GE. Quiambao LG. Stokes BJ. J. Am. Chem. Soc. 2016; 138: 6107
• 8 Ojha DP. Gadde K. Prabhu KR. Org. Lett. 2016; 18: 5062
• 9 Xuan Q. Song Q. Org. Lett. 2016; 18: 4250
• 10a Xia YT. Sun XT. Zhang L. Luo K. Wu L. Chem. Eur. J. 2016; 22: 17151
• 10b Sharma S. Kumar M. Kumar V. Kumar N. J. Org. Chem. 2014; 79: 9433
• 10c Orlandi M. Benaglia M. Tosi F. Annunziata R. Cozzi F. J. Org. Chem. 2016; 81: 3037
• 10d Kumar M. Sharma U. Sharma S. Kumar V. Singh B. Kumar N. RSC Adv. 2013; 3: 4894
• 10e Gao Y. Ma D. Wang C. Guan J. Bao X. Chem. Commun. 2011; 47: 2432
• 10f Oda S. Shimizu H. Aoyama Y. Ueki T. Shimizu S. Osato H. Takeuchi Y. Org. Process Res. Dev. 2011; 16: 96
• 10g Orlandi M. Tosi F. Bonsignore M. Benaglia M. Org. Lett. 2015; 17: 3941
• 11a Kong W. Wang Q. Zhu J. Angew. Chem. Int. Ed. 2017; 56: 3987
• 11b Zhou Y. Zhou H. Liu S. Pi D. Shen GS. Tetra­hedron 2017; 73: 3898
• 12a Zhou XF. Sun YY. Wu YD. Dai JJ. Xu J. Huang Y. Xu HJ. Tetrahedron 2016; 72: 5691
• 12b Ding W. Song Q. Org. Chem. Front. 2016; 3: 14
• 13 Wei Y. Zhao C. Xuan Q. Song Q. Org. Chem. Front. 2017; 4: 2291
• 14a Liu S. Zhou Y. Sui Y. Liu H. Zhou H. Org. Chem. Front. 2017; 4: 2175
• 14b Pi D. Zhou H. Zhou Y. Liu Q. He R. Shen G. Uozumi Y. Tetrahedron 2018; 74: 2121
• 15 Aniline (2a) Nitrobenzene (123 mg, 1.0 mmol), B₂(OH)₄ (448 mg, 5.0 mmol, 5.0 equiv), and H₂O (3.0 mL) were added to a 10 mL tube. The reaction mixture was stirred at 80 °C for 8 h. When the reaction was complete (monitored by TLC), the mixture was cooled to r.t. and extracted with ethyl acetate (3 × 20 mL). The combined organic phase was dried with anhydrous Na₂SO₄, filtered, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography. Colorless oil (92 mg, 99%); ¹H NMR (400 MHz, CDCl₃): δ = 7.27–7.22 (m, 2 H), 6.87–6.83 (m, 1 H), 6.76 (dd, J₁ = 7.6 Hz, J₂ = 0.8 Hz, 2 H), 3.66 (br, 2 H) ppm; ¹³C NMR (101 MHz, CDCl₃): δ = 146.60, 129.49, 118.72, 115.30 ppm.