Ethyl cyclopentanecarboxylate → HCID 10253447, Verbindung

Beteiligte Stoffe

Reaktionsschritte

3-(4-Phenyl-benzyl)-7-trifluoromethylsulfonyloxy-4-chromanone (35.0 g, 91.0 mmole, prepared from the product of Example 2C with biphenyl aldehyde using the procedures of Example 2D and Example 2E, was dissolved in a mixture of dimethylformamide (230 mL) and dimethoxyethane (230 mL). To this solution was added in the following order, tris(2-methylphenyl)phosphine (7.48 g, 24.6 mmole), bis(benzonitrile)palladium (II) chloride (2.44 g, 6.37 mmole), the trimethylsilyl ketene acetal of ethyl cyclopentanecarboxylate (29.26 g, 136.5 mmole), and a 1.0M ethereal solution of zinc chloride (25 mL, 25 mmole). The resulting clear yellow solution was refluxed for about 1 hour. Additional trimethylsilyl ketene acetal (9.75 g, 45.5 mmole) was added at this point and the reflux continued for about another 1 hour. The cooled mixture was diluted with water (1 L) and extracted with ether. The combined ether extracts were washed with water (1 L) and then dried over magnesium sulfate. Filtration and concentration of the extract gave a yellow oil which was chromatographed on silica gel (8:92 ethyl acetate/hexane). This yielded 22.13 g (64%) of the title compound of this Example 5A as a white solid; m.p. 50-56 ° C.; 1H NMR (CDCl3): 1.23 (3H, t, J=7.0), 1.75 (4H, m), 1.9 (2H, m), 2.6 (2H, m), 2.70 (1H, dd, J=10.5, 13.8), 2.9 (1H, m), 3.26 (1H, dd, J=4.3, 13.8), 4.08 (2H, d, J=7.0), 4.15 (1H, dd, J=8.2, 11.5), 4.35 (dd, J=4.3, 11.5), 6.95 (1H, d, J=1.7), 7.02 (1H, dd, J=1.7, 8.3), 7.2-7.4 (5H, m) 7.84 (1H, d, J=8.3).

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