Benzene, 1-bromo-3-iodo- → 1-Bromo-3-ethynylbenzene

Participants

Reaction Steps

To an oven-dried flask under N2 was added 1-bromo-3-iodobenzene (5.00 g, 17.73 mmol), anhydrous, degassed THF (100 mL), dichlorobis(triphenyl-phosphine)palladium(II) (620 mg, 0.88 mmol), copper(I) iodide (100 mg, 0.53 mmol), TEA (7.15 g, 71 mmol), and TMS acetylene (1.91 g, 20 mmol). After stirring overnight at rt, the reaction was washed with brine (100 mL), organic layer separated, concentrated under reduced pressure, adsorbed to silica gel and purified by column chromatography (5% EtOAc in hexanes) to afford the desired product (3.57 g, 80%) as a clear oil. This was dissolved in 100 ml 1:1 THF:MeOH and to this was added water (10 mL), and K2CO3 (5.87 g, 43 mmol). After stirring overnight at rt, the reaction was washed with brine (100 mL), adsorbed to silica gel and purified by LC (5% EtOAc in hexanes) to afford the alkyne (1.92 g, 75%) as a pale yellow oil. 1H NMR (400 MHz, CDCl3) δ 3.10 (s, 1H), 7.17 (t, J=7.69 Hz, 1H), 7.38-7.44 (m, 1H), 7.45-7.48 (m, 1H), 7.61-7.62 (s, 1H).

Provenance & Evidence