The first solid-phase synthesis of oligothiophenes

Abstract

The solid-phase synthesis of asymmetric oligothiophenes on a chloromethylated macroporous resin, using an alternating sequence of bromination and Stille coupling reactions, has been used to afford oligomers up to the pentamer in excellent yield and purity.

References

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14. Methyl 4″,4‴,4‴′-trioctyl-2,2′:5′,2″:5″,2‴:5‴,2‴′-quinquethiophene-5-carboxylate (8e): 0.1903 g of 8(theory: 0.486 mequiv. g^–1 or 0.092 mmol) afforded 67.3 mg (0.083 mmol) of 8e in a yield of 90%. Mp 49 °C (DSC); λ_max(CHCl₃)/nm 422; v(KBr)/cm^–1 3095, 3069, 2953, 2924, 2851, 1710, 957, 934, 847, 822, 805, 786, 745; δ(500 MHz, CDCl₃) 7.70 (d, J 3.9, 1H), 7.18 (d, J 3.8, 1H), 7.12 (d, J 3.9, 1H), 7.07 (d, J 3.8, 1H), 7.02 (s, 1H), 6.97 (2 d, 2H), 6.90 (s, 1H), 3.89 (s, 3H), 2.75 (2 t, J 8.0, 4H), 2.61 (t, J 7.7, 2H), 1.66 (m, 6H), 1.49–1.14 (m, 30H), 0.88 (m, J 6.8, 9H); δ_C(125 MHz, CDCl₃) 162.45, 143.92, 143.69, 140.32, 139.63, 137.97, 135.35, 134.72, 134.33, 133.90, 133.19, 131.29, 131.16, 130.55, 128.66, 127.22, 127.15, 125.98, 124.21, 123.68, 120.10, 52.20, 31.88, 30.57, 30.49, 30.47, 30.43, 29.55, 29.54, 29.45, 29.43, 29.42, 29.40, 29.35, 29.27, 22.67, 14.10; HRMS (FAB) calc. for C₄₆H₆₂O₂S₅ 806.3353; found 806.3349 (Calc. for C₄₆H₆₂O₂S₅: C, 68.44; H, 7.74; S, 19.86. Found: C, 68.60; H, 8.00; S, 19.63%).