Water → HCID 66969761, compound

Participants

Reaction Steps

Ytterbium(III) trifluoromethanesulphonate (3.25 g, 5.23 mmol) in 116 ml of dichloromethane is admixed dropwise at room temperature with ethyl trifluoropyruvate (9.55 ml, 78.5 mmol). Following the addition of 4-isopropyl-2-methoxy-1-(1-methylpropenyl)benzene (10.7 g, 52.37 mmol), in solution in 29.5 ml of dichloromethane, the reaction mixture is stirred at room temperature for two days. In parallel a second batch is carried out with the same quantities and under the same conditions. Water (100 ml) is added to each of the two reactions. For further working up, the two batches are combined. The dichloromethane phase is separated off and the aqueous phase is extracted a further time with dichloromethane (300 ml). The combined organic extracts are washed with water (100 ml) and brine (100 ml) and then dried (Na2SO4). After removal of the solvent on a rotary evaporator, the residue is purified by repeated chromatography on silica gel (eluent: ethyl acetate/hexane). The yield of ene product, which is used in the next stage, is 9.08 g, only 40% being the described compound and 60% being the corresponding ethyl 4-(4-isopropyl-2-methoxyphenyl)-2-hydroxy-3-methyl-2-(trifluoromethyl)pent-4-enoate.

Provenance & Evidence