反应详情

To a stirred solution of known tert-butyl L-(+)-lactate (0.88 g), 4-(2',4'-dichlorophenoxy)phenol (1.54 g) and triphenylphosphine (1.58 g) in dry tetrahydrofuran (58 ml) on an ice bath, diethylazodicarboxylate (0.95 ml) was added dropwise. After the addition, the ice bath was removed and the mixture was further stirred at room temperature for 25 hours. The reaction mixture was evaporated with a rotary evaporator. The residue thus obtained was purified by silica gel chromatography [silica gel 399 g, eluant:ethyl acetate-hexane (1:30)] to give tert-butyl (2R)-(+)-2-[4'-(2",4"-dichlorophenoxy)phenoxy]propionate as a colorless oily substance (0.98 g). This was left to stand at room temperature under high vacuum (0.25 Torr) for 2 hours and under atmosphere for several days to crystallize. A crystalline substance thus formed was washed with a small amount of hexane and filtered to give colorless crystals.

1. additionAfter the addition
2. customthe ice bath was removed
3. customThe reaction mixture was evaporated with a rotary evaporator
4. customThe residue thus obtained
5. customwas purified by silica gel chromatography [silica gel 399 g, eluant:ethyl acetate-hexane (1:30)]