C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.[I:20]I.N1C=CN=C1.[CH3:27][O:28][C:29](=[O:37])[CH2:30][O:31][CH2:32][C:33]#[C:34][CH2:35]O>C(Cl)Cl>[CH3:27][O:28][C:29](=[O:37])[CH2:30][O:31][CH2:32][C:33]#[C:34][CH2:35][I:20]
Triphenylphosphine (6.23 g, 23.8 mmol), iodine (6.03 g, 23.8 mmol) and imidazole (1.57 g, 23.8 mmol) were added sequentially to a solution of (4-hydroxy-but-2-ynyloxy)-acetic acid methyl ester (3.13 g, 19.8 mmol) in CH2Cl2 (30 mL). After 1 h at rt, the reaction was filtered through activity I basic alumina, washing with 20% EtOAc/Hexane. The filtrate was concentrated in vacuo then purified by flash column chromatography on silica gel (Hexane→20% EtOAc/Hexane, gradient) to afford 2.05 g (39%) of (4-iodo-but-2-ynyloxy)-acetic acid methyl ester.
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