Compound 4
5-(3,5-bis(trifluoromethyl)phenyl)-3-(2-(4-methoxyphenyl)cyclopent-1-en-1-yl)-2-methylthiophene
From: Light-driven molecular trap enables bidirectional manipulation of dynamic covalent systems
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Compound data: 1H NMR
Compound data: 13C NMR
Compound data: 19F NMR
Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.
Under an argon atmosphere, a Schlenk flask was charged with triflate 3 (2.58 g, 8.0 mmol, 1.0 eq.), boronic ester 1 (4.37 g, 10.0 mmol, 1.25 eq.), caesium carbonate (7.82 g, 24.0 mmol, 3.0 eq.), palladium(II) acetate (90.0 mg, 0.4 mmol, 5.0 mol%.), SPhos (0.33 g, 0.8 mmol, 10 mol% eq.), and 40 mL of dry and degassed 1,4-dioxane. After stirring for 16 hours at 110 °C, the crude reaction mixture was diluted with ethyl acetate, filtered over a pad of silica gel, and purified by flash column chromatography (SiO2; cyclohexane/ethyl acetate 50:1), providing the product (1.7 g, 45%) as a colorless solid. 1H NMR (500 MHz, CDCl3, 25 °C): δ = 7.91 (s, 2H), 7.70 (s, 1H), 7.22 (s, 1H), 7.15–7.07 (m, 2H), 6.82–6.71 (m, 2H), 3.77 (s, 3H), 2.91 (tt, 3,4J(H,H) = 7.5, 2.2 Hz, 2H), 2.79 (tt, 3,4J(H,H) = 7.5, 2.2 Hz, 2H), 2.07 (p, 3J(H,H) = 7.5 Hz, 2H), 2.02 (s, 3H) ppm. 13C{1H} NMR (126 MHz, CDCl3, 25 °C): δ = 158.40 (s), 138.67 (s), 138.14 (s), 136.80 (s), 136.76 (s), 136.69 (s), 132.29 (q, 2J(C,F) = 33.3 Hz), 131.19 (s), 130.43 (s), 128.45 (s), 126.62 (s), 125.33–124.76 (m), 123.42 (q, 1J(C,F) = 272.9 Hz), 120.17 (p, 3J(C,F) = 3.9 Hz)*, 113.63 (s), 55.30 (s), 39.97 (s), 37.28 (s), 22.48 (s), 14.40 (s) ppm. *Full assignment of heptet splitting is not possible due to low intensity. 19F NMR (471 MHz, CDCl3, 25 °C): δ = –63.25 (s, 6F) ppm. MS (ESI+): m/z calculated for C25H21F6OS [M+H]+: 483.122, found: 483.121.
