Tetrahydrofuran → (2S)-2-ethyl-2-hydroxy-3-methyl-but-3-enoic acid (1R,2S,5R)-5-methyl-2-(1-methyl-1-phenyl-ethyl)-cyclohexyl ester

Beteiligte Stoffe

Reaktionsschritte

To a solution of 4.200 g of compound (17) as obtained from example 11 (13.27 mmol) in 168 mL tetrahydrofuran were added dropwise at −78° C. 39.8 mL isopropenylmagnesium bromide (19.91 mmol, 1.5 eq). After additional 50 min, the reaction mixture was quenched by addition of 110 mL saturated aqueous ammonium chloride solution, and was extracted twice with 110 mL ethyl acetate. The combined organic phases were washed with 110 mL brine, dried over 15 g sodium sulfate and were filtered. The filter cake was washed with 30 mL ethyl acetate. The organic phase was evaporated to dryness in a rotary evaporator (40° C., 8 mbar) yielding the title compound (4.790 g, 101% by weight, dr=93:7)as a yellow oil.

Herkunft & Nachweise