Triethylamine → 4-Cyclopropylethynyl-3-methyl-benzofuran-2-carboxylic acid ethyl ester

HRID 29287Notes

Reaction equation

[CH2:1]([O:3][C:4]([C:6]1[O:7][C:8]2[CH:15]=[CH:14][CH:13]=[C:12](OS(C(F)(F)F)(=O)=O)[C:9]=2[C:10]=1[CH3:11])=[O:5])[CH3:2].CCN(CC)CC.[CH:31]1([C:34]#[C:35][Si](C)(C)C)[CH2:33][CH2:32]1.[F-].C([N+](CCCC)(CCCC)CCCC)CCC>CN(C=O)C.Cl[Pd](Cl)([P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)[P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C(OCC)(=O)C.CCCCCC>[CH2:1]([O:3][C:4]([C:6]1[O:7][C:8]2[CH:15]=[CH:14][CH:13]=[C:12]([C:35]#[C:34][CH:31]3[CH2:33][CH2:32]3)[C:9]=2[C:10]=1[CH3:11])=[O:5])[CH3:2]

Participants

Conditions

Temperature: 80 °C

Procedure

To the product of Example 20, Step 1, 3-methyl-4-trifluoromethanesulfonyloxy-benzofuran-2-carboxylic acid ethyl ester (1.8 g, 5.1 mmol, 1 eq), in 2 mL of DMF under nitrogen was added 200 mg of PdCl2(PPh3)2 (0.28 mmol, 0.05 eq), Et3N (2.85 mL, 20.4 mmol, 4 eq), cyclopropylethynyl-trimethylsilane (1 g, 7.2 mmol, 1.4 eq), and tetrabutylammonium fluoride (5.1 mL, 1.0 M in THF, 5.1 mmol, 1 eq). The reaction mixture was sealed and heated to 80° C. for 12 h. After workup and column chromatography (2% ethyl acetate/hexane), 4-cyclopropylethynyl-3-methyl-benzofuran-2-carboxylic acid ethyl ester was obtained in 15% yield (202.6 mg). 1H NMR (400 MHz, CD3OD) δ ppm 0.7 (m, 2 H) 0.9 (m, 2 H) 1.3 (t, J=7.1 Hz, 3 H) 1.5 (m, 1 H) 2.7 (s, 3 H) 4.3 (q, J=7.2 Hz, 2 H) 7.2 (m, 1 H) 7.3 (dd, J=8.3, 7.3 Hz, 1 H) 7.4 (m, 1 H).

Workup

customThe reaction mixture was sealed

Sources & evidence

ORD record: ord-b43b0b33ea84422d9688771621b8020f
Source dataset: uspto-grants-2008_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07420001B2

Reaction notes

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