Dimethylformamide → HCID 131724657, compound

Participants

Reaction Conditions

Reaction Steps

A 50 mL round bottom flask was charged with a Teflon coated stir bar, 4-iodophenylmethane (408 mg, 2.0 mmol), 1-(3′5′-di-tert-butylstyryl)-4-(4′-vinylstyryl)benzene (0.84 g, 2.0 mmol), Pd(OAc)2 (22.45 mg, 0.1 mmol), K2CO3 (690 mg, 5.0 mmol), n-Bu4NBr (665 mg, 2.0 mmol) and DMF (16 mL). The mixture was degassed with 4 freeze-pump-thaw cycles and heated at 90° C. for 48 hours. The reaction was cooled to room temperature, diluted with CH2Cl2, washed with brine, dried over MgSO4 and the solvent was removed under reduced pressure. The crude product was purified on a silica gel column (20% CH2Cl2/hexanes) to give a yellow greasy solid which contains cis-trans isomers. The isomers were dissolved in 150 mL benzene and degassed with 4 freeze-pump-thaw cycles. The solution was irradiated with Blak-Ray long UV lamp for 60 minutes and the solvent was removed under reduced pressure. The isomerized product was repurified on a silica gel column (20% CH2Cl2/hexanes) to give a yellow solid (yield 71%). 1H NMR (CDCl3): δ 7.51-7.54 (overlapping signals, 9H), 7.35-7.39 (overlapping signals, 5H), 7.28 (t, J=7.50 Hz, 1H), 7.19 (d, J=16.3 Hz, 1H), 7.13 (complex, 4H), 7.10 (d, J=16.3 Hz, 1H), 1.37 (s, 18H). 13C NMR (CDCl3): δ 151.28, 137.54, 136.66, 129.96, 128.93, 128.78, 128.49, 128.20, 127.76, 127.09, 127.04, 127.01, 126.73, 121.09, 31.69. Exact Mass (FAB, NBA) for M+ (C38H40): calculated 496.3143; found 496.3189.

Provenance & Evidence