Tributyl(prop-1-yn-1-yl)stannane → 3-Methyl-4-prop-1-ynyl-benzofuran-2-carboxylic acid ethyl ester

関与物質

反応手順

To 3-methyl-4-trifluoromethanesulfonyloxy-benzofuran-2-carboxylic acid ethyl ester (550 mg, 1.6 mmol, 1 eq), the product of Example 20, Step 1, in 5 mL of toluene under nitrogen was added 60 mg of Pd(PPh3)4 (0.05 mmol, 0.03 eq) and tributyl-prop-1-ynyl-stannane (0.55 mL, 1.8 mmol, 1.13 eq). The resulting reaction mixture was heated to reflux for 18 h. After work up and column chromatography (3% ethyl acetate/hexane), 3-methyl-4-prop-1-ynyl-benzofuran-2-carboxylic acid ethyl ester was obtained in 14% yield (56 mg). 1H NMR (400 MHz, CDCl3) δ ppm 1.4 (t, J=7.1 Hz, 3 H) 2.1 (s, 3 H) 2.8 (s, 3 H) 4.5 (q, J=7.1 Hz, 2 H) 7.3 (m, 2 H) 7.5 (dd, J=7.6, 1.8 Hz, 1 H).

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