Diisopropylamine → Ethyl (E)-4-hydroxy-3-methyl-6-oxo-6-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-2-naphthalenyl)-2-hexenoate

Beteiligte Stoffe

Reaktionsschritte

To a solution of diisopropylamine (0.5 mL, 3.52 mmol) in 7 mL of THF at -78° C. under argon was added a 1.6M solution of n-butyllithium in hexane (2.2 mL, 3.52 mmol). The mixture was stirred for 25 min, and a solution of ketone 39 (0.78 g, 3.2 mmol) in 4 mL of THF was added slowly. The mixture was stirred for 20 min, and a solution of ethyl (E)-3-formyl-2-butenoate 40 (0.45 g, 3.2 mmol) (ethyl (E)-3-formyl-2-butenoate 40 is readily available from Fluka) in 3 mL of THF was added slowly. The mixture was stirred for 35 min at -78° C., poured into saturated aqueous NH4Cl, and extracted with 40% ethyl acetate/hexane. The combined organic layers were dried over anhydrous MgSO4, filtered, and concentrated to afford a light-yellow solid. Flash chromatography yielded the desired alcohol 41 as a white crystalline solid (0.98 g, 80%): m.p. 126°-128° C.; Rf 0.13 (10% ethyl acetate/hexane). The structure of the product was also confirmed using IR, 1H NMR and mass spectroscopy.

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