Allyl bromide → diisopropyl (2R,3S)-2-allyl-3-hydroxybutanedioate

Participants

Reaction Conditions

Reaction Steps

To a cold (−78° C.) solution of diisopropyl (S)-(−)-malate (4.74 mL; 22.9 mmol; 1.0 eq.) in anhydrous THF (8.50 mL) was slowly added under argon lithium bis(trimethylsilyl)amide (48.1 mL; 1.0 M in THF; 48.11 mmol; 2.1 eq.) keeping the temperature below −66° C. After 45 min of addition, the reaction mixture was stirred at −78° C. for 2 h, then the temperature of the reaction mixture was allowed to reach 11° C. After 1 h at that temperature, the mixture was cooled at −78° C. and allyl bromide (2.9 mL; 34.4 mmol; 1.5 eq.) was added. The solution was stirred overnight allowing the temperature to reach RT. The reaction was then quenched with ice water and an aqueous saturated solution of NH4Cl. The aqueous layer was extracted 3 times with EtOAc and the combined organic layers were washed with a saturated solution of NaCl, dried over MgSO4 and evaporated to obtain an orange oil (5.4 g). Purification by chromatography (SiO2, 10/90 EtOAc/c-hex) gave the title product as a colorless oil (3.05 g, 51.5%). 1H NMR (CDCl3, 300 MHz) δ 5.76-5.59 (m, 1H), 5.07-4.80 (m, 4H), 4.08 (d, J=2.3 Hz, 1H), 3.03 (br s, 1H), 2.80-2.72 (m, 1H), 2.53-2.41 (m, 1H), 2.34-2.21 (m, 1H), 1.14 (d, J=6.4 Hz, 6H), 1.07 (d, J=6.4 Hz, 6H).

Provenance & Evidence