Palladium-Catalyzed Hydroarylation of Diazoacetic Ester

Abstract

The novel procedure for the Pd-catalyzed hydroarylation of α-diazoacetic ester is reported. In the presence of a catalytic amount of PdCl₂(PPh₃)₂ the three-component reaction of aryl ­iodides, ethyl diazoacetate, and formic acid proceeds smoothly ­resulting in the formation of a series of arylacetates.

Key words

hydroarylation - diazoacetic ester - arylacetates - ­palladium catalysis - cross-coupling

• References and Notes


For some reviews, see:
• 1a Ye T, McKervey MA. Chem. Rev. 1994; 94: 1091
• 1b Zhang Z, Wang J. Tetrahedron 2008; 64: 6577
• 1c Doyle MP, Duffy R, Ratnikov M, Zhou L. Chem. Rev. 2010; 110: 704

For recent reviews, see:
• 2a Zhang Y, Wang J. Eur. J. Org. Chem. 2011; 1015
• 2b Zhang Y, Wang J. Chem. Commun. 2009; 5350
• 3 Peng C, Cheng J, Wang J. J. Am. Chem. Soc. 2007; 129: 8708

Selected results:
• 4a Greenman KL, Van Vranken DL. Tetrahedron 2005; 61: 6438
• 4b Peng C, Wang Y, Wang J. J. Am. Chem. Soc. 2008; 130: 1566
• 4c Peng C, Yan G, Wang Y, Jiang Y, Zhang Y, Wang J. Synthesis 2010; 4154
• 5a Devine SK. J, Van Vranken DL. Org. Lett. 2007; 2047
• 5b Devine SK. J, Van Vranken DL. Org. Lett. 2008; 1909
• 5c Kadirka R, Devine SK. J, Adams CS, Van Vranken DL. Angew. Chem. Int. Ed. 2009; 48: 3677

For selected examples, see:
• 6a Takeda T, Gonda R, Hatano K. Chem. Pharm. Bull. 1997; 45: 697
• 6b Kimura Y, Nishibe M, Nakajima H, Hamasaki T. Agric. Biol. Chem. 1991; 55: 1137
• 7 Curhan SG, Eavey R, Shargorodsky J, Curhan GC. Am. J. Med. 2010; 123: 231
• 8 Harrington PJ, Lodewijk E. Org. Process Res. Dev. 1997; 1: 72
• 9 Musa KA. K, Matxain JM, Eriksson LA. J. Med. Chem. 2007; 50: 1735
• 10 Bandgar BP, Sarangdhar RJ, Ahamed FA, Viswakarma S. J. Med. Chem. 2011; 54: 1202
• 11 Adams R, Thal AF. Org. Synth., Coll. Vol. I 1941; 436
• 12 Duan J, Jiang J, Gong J, Fan Q, Jiang D. J. Mol. Catal. A: Chem. 2000; 159: 89
• 13 Fructos MR, Belderrain TR, de Fremont P, Scott NM, Nolan SP, Diaz-Requejo MM, Perez PJ. Angew. Chem. Int. Ed. 2005; 44: 5284
• 14a Hama T, Hartwig JF. Org. Lett. 2008; 1545
• 14b Biscoe MR, Buchwald SL. Org. Lett. 2009; 1773
• 15 Broering M, Brandt CD, Stellwag S. Chem. Commun. 2003; 2344
• 16 Albeniz AC, Espinet P, Manrique R, Perez-Mateo A. Angew. Chem. Int. Ed. 2002; 41: 2363
• 17 Sole D, Vallverdu L, Solans X, Font-Bardia M, Bonjoch J. Organometallics 2004; 23: 1438
• 18 Typical Procedure for the Pd-Catalyzed Cross-Coupling between Aryl Iodides and EDA To a mixture of aryl iodide 1a–h (1 mmol), PdCl₂(PPh₃)₂ (35 mg, 0.05 mmol) in a Schlenk flask under argon atmosphere, Et₃N (254 mg, 2.5 mmol) and formic acid (69 mg, 1.5 mmol) in MeCN (3 mL) were added. The mixture was stirred and heated to 70 °C, then EDA (171 mg, 1.5 mmol) in MeCN (2 mL) was added in small portions for 40–60 min. The mixture was stirred at the same temperature until 1a–h disappeared (the total time of heating indicated in Table 2). The solvent was evaporated in vacuo. Purification of the mixture by column chromatography (EtOAc–hexane = 1:10 v/v) gave the pure compounds 2a–h.
• 19 Selected Data for Synthesized Compounds Compound 2a: colorless oil. ¹H NMR (400 MHz, CDCl₃): δ = 7.98 (d, 2 H, J = 7.2 Hz), 7.35 (d, 2 H, J = 7.2 Hz), 4.14 (q, 2 H, J = 7.0 Hz), 3.88 (s, 3 H), 3.65 (s, 2 H), 1.23 (t, 3 H, J = 7.1 Hz). ¹³C NMR (100 MHz, CDCl₃): δ = 170.8, 166.8, 139.3, 129.8, 129.3, 129.0, 61.0, 52.0, 41.3, 14.1. IR (film): 1733, 1615, 1290 cm^–1. Anal. Calcd for C₁₂H₁₄O₄: C, 64.85; H, 6.35. Found: C, 64.92; H, 6.39. Compound 2e: yellow oil. ¹H NMR (400 MHz, CDCl₃): δ = 8.14 (m, 2 H), 7.62 (m, 1 H), 7.51 (m, 1 H), 4.18 (q, 2 H, J = 7.0 Hz), 3.73 (s, 2 H), 1.27 (t, 3 H, J = 7.1 Hz). ¹³C NMR (100 MHz, CDCl₃): δ = 170.3, 148.2, 136.0, 135.6, 129.4, 124.4, 122.2, 61.4, 41.0, 14.1. IR (film): 1740, 1540, 1360 cm^–1. Anal. Calcd for C₁₀H₁₁NO₄: C, 57.41; H, 5.30; N, 6.70. Found: C, 57.48; H, 5.39; N, 6.75. Compound 2g: colorless oil. ¹H NMR (400 MHz, CDCl₃): δ = 8.52 (m, 2 H), 7.64 (d, 1 H, J = 7.8 Hz), 7.25 (m, 1 H), 4.16 (q, 2 H, J = 7.0 Hz), 3.61 (s, 2 H), 1.25 (t, 3 H, J = 7.1 Hz). ¹³C NMR (100 MHz, CDCl₃): δ = 170.6, 150.3, 148.5, 136.7, 129.8, 128.5, 123.3, 61.1, 38.5, 14.1. IR (film): 1730, 1600 cm^–1. Anal. Calcd for C₉H₁₁NO₂: C, 65.44; H, 6.71; N, 8.48. Found: C, 65.54; H, 6.66; N, 8.57.