[Br-].[CH3:2][CH:3]([O:7][C:8]1[CH:33]=[CH:32][C:31]([I:34])=[CH:30][C:9]=1[CH2:10][P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)[C:4](=O)[CH3:5].[Na].[CH2:36](OCC)C.O>C(O)C>[I:34][C:31]1[CH:32]=[CH:33][C:8]2[O:7][C:3]([CH3:2])([CH3:36])[C:4]([CH3:5])=[CH:10][C:9]=2[CH:30]=1
To a suspension of 2-(1-methyl-2-oxo-propyloxy)-5-iodobenzyltriphenylphosphonium bromide (0.71 g, 0.00108 mol) in absolute ethanol (3 ml) was added dropwise at room temperature a solution of sodium (0.025 g) in absolute ethanol (1 ml). After twelve hours at room temperature, diethyl ether and water were added. The organic phase was separated, dried and evaporated. The residue was chromatographed on silica gel, eluting with a mixture of dichloromethane/heptane (50/50) to give 0.29 g (85%) of 6-iodo-2,2,3-trimethyl-1(2H)-benzopyran, as an oil, 1NMR (CDCl3): δ1.4 (s, 6H), 1.8 (s, 3H), 6.0 (s, 1H), 6.55 (d, 1H), 7.2 (d, 1H), 7.35 (d, 1H).
Wird geladen…
