Water → 2-Tert-butoxycarbonyl-7-(methylthio)-1,2,3,4,10,10a-hexahydropyrazino[1,2-a]indole

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Reaction Steps

Triphenylphosphine (28 mg) was added in 1 portion to a stirred solution of palladium(II) acetate (6 mg) in THF (2.5 mL) at room temperature under Ar. After stirring at room temperature under Ar for 10 min a solution of 2-tert-butoxycarbonyl-7-iodo-1,2,3,4,10,10a-hexahydropyrazino[1,2-a]indole (0.20 g, 0.5 mmol) in THF (5 mL) was added. The reaction was stirred at room temperature for 10 min then a solution of (methylthio)tributyltin (0.35 g, 1 mmol) in THF (2.5 mL) was added. The reaction was heated to reflux and stirred for 2 days. After allowing to cool to room temperature the mixture was poured into water (50 mL) and extracted, with ethyl acetate (3×30 mL). The combined organic extracts were washed with brine (1×50 mL), dried (magnesium sulfate), filtered and the solvent removed under vacuum to leave a crude oil. The oil was purified by flash column chromatography [SiO2; ethyl acetate-heptane (1:20)] to give the product as a yellow oil (0.08 g, 50%). NMR δH (400 MHz; CDCl3) 6.97 (1H, d, J 7.5 Hz), 6.56 (1H, dd, J 7.5, 1.5 Hz), 6.36 (1H, d, J 1.5 Hz), 3.94–4.26 (2H, m), 3.35–3.49 (2H, m), 2.78–2.96 (4H, m), 2.49–2.55 (1H, m), 2.44 (3H, s), 1.46 (9H, s).

Provenance & Evidence