Triphenylphosphine → 1-Acetyl-6-bromo-2,3-dihydro-5-(1,4-dioxaspiro[4,5]dec-7-en-8-yl)methoxy-1H-indole

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Reaction Steps

1-Acetyl-6-bromo-2,3-dihydro-1H-indol-5-ol (Tetrahedron 1973, 29, 1115) (1.10 g, 4.3 mmol), 1,4-dioxaspiro[4,5]dec-7-ene-8-methanol (D11, 0.88 g, 5.2 mmol) and triphenylphosphine (1.36 g, 5.2 mmol) were stirred under Ar in dry THF (50 ml) as diethyl azodicarboxylate (0.82 ml, 5.2 mmol) was added dropwise. The mixture was stirred for 1 h, diluted with ethyl acetate (100 ml), washed with brine, dried (Na2SO4) and evaporated to give a dark oil. Chromatography on silica gel, eluting with 0-5% methanol/dichloromethane, gave the title compound (3.17 g) contaminated by substantial amounts of triphenylphosphine and diethyl azodicarboxylate-derived residues (NMR).

Provenance & Evidence