A Mild and Clean Method for Oxidative Formation of Amides from Aldehydes and Amines

Abstract

A metal-free direct oxidative formation of amides from aldehydes and amines using a hypervalent iodine(III) reagent or an ion-supported hypervalent iodine(III) reagent as a recyclable oxidant under mild conditions is reported.

Key words

(diacetoxyiodo)benzene - ion-supported hypervalent iodine(III) reagent - direct oxidative formation of amides - amines - aldehydes

References and Notes

• 1 Humphrey JM. Chamberlin AR. Chem. Rev.  1997,  97:  2243 
• 2 Katritzky AR. He H.-Y. Suzuki K. J. Org. Chem.  2000,  65:  8210 
• 3a Mukhopadhyay M. Reddy MM. Maikap GG. Iqbal J. J. Org. Chem.  1995,  60:  2670 
• 3b Callens E. Burtonb AJ. Barretta AGM. Tetrahedron Lett.  2006,  47:  8699 
• 4a Liley MJ. Johnson T. Gibson SE. J. Org. Chem.  2006,  71:  1322 
• 4b Perreux L. Loupy A. Volation F. Tetrahedron  2002,  58:  2155 
• 5 Uenoyama Y. Fukuyama T. Nobuta O. Matsubara H. Ryu I. Angew. Chem. Int. Ed.  2005,  44:  1075 
• 6a Cho SH. Yoo EJ. Bae I. Chang S. J. Am. Chem. Soc.  2005,  127:  16046 
• 6b Whiting M. Fokin VV. Angew. Chem. Int. Ed.  2006,  45:  3157 
• 7a Trost BM. Fleming I. Comprehensive Organic Synthesis   Vol. 6:  Winterfeld E. Pergamon; Oxford: 1991. 
• 7b Sheeham JC. Hess GP. J. Am. Chem. Soc.  1955,  77:  1067 
• 7c Lawrence RM. Biller SA. Fryszman OM. Poss MA. Synthesis  1997,  553 
• 8a Tamaru Y. Yamada Y. Yoshida Z. Synthesis  1983,  474 
• 8b Naota T. Murahashi S. Synlett  1991,  693 
• 8c Tillack A. Rudloff I. Beller M. Eur. J. Org. Chem.  2001,  523 
• 9 Yoo W.-J. Li C.-J. J. Am. Chem. Soc.  2006,  128:  13064 
• 10a Wirth T. Angew. Chem. Int. Ed.  2005,  44:  3656 
• 10b Richardson RD. Wirth T. Angew. Chem. Int. Ed.  2006,  45:  4402 
• 11a Zhdankin VV. Stang PJ. Chem. Rev.  2002,  102:  2523 
• 11b Stang PJ. Zhdankin VV. Chem. Rev.  1996,  96:  1123 
• 12 Qian WX. Jin EL. Bao WL. Zhang YM. Angew. Chem. Int. Ed.  2005,  44:  952 
• 13 Qian WX. Pei L. Synlett  2006,  709 
• 14a Cui Y. He C. Angew. Chem. Int. Ed.  2004,  43:  4210 
• 14b Davies HML. Long MS. Angew. Chem. Int. Ed.  2005,  44:  3518 
• 14c Espino CG. Wehn PM. Chow J. Du Bois J. J. Am. Chem. Soc.  2001,  123:  6935 
• 14d Fleming JJ. Fiori KW. Du Bois J. J. Am. Chem. Soc.  2003,  125:  2028 
• 14e Liang J.-L. Yuan S.-X. Huang J.-S. Yu W.-Y. Che C.-M. Angew. Chem. Int. Ed.  2002,  41:  3465 
• 15 Zhang L. Kauffman GS. Pesti JA. Yin J. J. Org. Chem.  1997,  62:  6918 
• 16 Chan J. Baucom KD. Murry JA. J. Am. Chem. Soc.  2007,  129:  14106 
• 19 Gao J. Wang G.-W. J. Org. Chem.  2008,  73:  2955 

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All reagents and solvents were pure analytical grade materials purchased from commercial sources and were used without further purification, if not stated otherwise. All melting points are uncorrected. The NMR spectra were recorded in CDCl₃ on a Bruker Avance 400 MHz instrument with TMS as internal standard. TLC was carried out with 0.2 mm thick silica gel plates (GF254). The columns were hand packed with silica gel 60 (200-300 µm). All products were confirmed by ^¹H NMR and ^¹³C NMR. Unknown compounds were additionally confirmed by elemental analysis.
Typical Procedure for the Oxidative Amidation of Aldehydes with Amines by DIB: A solution of aldehyde (0.50 mmol, 1.0 equiv), DIB (0.75 mmol, 1.5 equiv), and two drops of H₂O in CHCl₃ (1 mL) was cooled to 0 ˚C under an inert atmosphere (N₂) and the amine (0.65 mmol, 1.3 equiv) was slowly added (about one drop in 1 h for 3 h). The reaction vessel was capped and the reaction mixture was stirred for 3 h at 0 ˚C and then for 17 h at r.t. The crude reaction mixture was purified by column chromatography on silica gel (EtOAc-hexane, 1:4). 3,4,5-Trimethoxy- N -propylbenzamide (Table 2, entry 9): white solid; mp 108 ˚C. ^¹H NMR (400 MHz, CDCl₃): δ = 7.00 (s, 2 H), 6.25 (br, 1 H), 3.89 (s, 6 H), 3.87 (s, 3 H), 3.40 (q, J = 6.8 Hz, 2 H), 1.60-1.69 (m, 2 H), 0.98 (t, J = 8.0 Hz, 3 H). ^¹³C NMR (100 MHz, CDCl₃): δ = 167.3, 153.1, 140.7, 130.3, 104.3, 60.8, 56.2, 41.8, 22.9, 11.4. Anal. Calcd for C₁₃H₁₉NO₄: C, 61.64; H, 7.56; N, 5.53; O, 25.27. Found: C, 61.60; H, 7.65; N, 5.60.

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The ionic liquid [dibmim]⁺[BF₄]^- was recovered and recycled in our previous work. Please refer to ref. 12.