Acetaldehyde → HCID 68772154, compound

Participants

Reaction Conditions

Reaction Steps

At −60° C., a solution of diisopropylamine (4.1 ml, 28.8 mmol) in tetrahydrofuran (30 ml) was treated with n-butyl lithium (18 ml, 1.6M in hexane, 28.8 mmol). The resulting solution was stirred at −30° C. for 20 min., cooled to −70° C., and treated with a solution of crude 1-(rel-(6R,7R)-7-methylspiro[4.5]decan-6-yl)ethanone (4.3 g, 22 mmol) in tetrahydrofuran (10 ml). The resulting solution was stirred 45 min. at −70° C., and treated within 15 min. with a solution of acetaldehyde (5 ml, 88.5 mmol) in tetrahydrofuran (10 ml). After 2 h stirring, the reaction mixture was poured into 2N aqueous HCl and ice (150 ml) and extracted twice with MTBE (100 ml). The combined organic phases were washed with water (50 ml), with a saturated aqueous NaCl solution (100 ml), dried (MgSO4), and concentrated. The crude product (5.5 g) was dissolved in toluene (60 ml). The resulting solution was treated with para-toluene sulfonic acid monohydrate (0.5 g, 2.8 mmol) and heated at 60° C. for 1.5 h. The reaction mixture was cooled, poured into a cold saturated aqueous solution of NaHCO3 (100 ml) and the aqueous phase was extracted with MTBE (80 ml). The combined organic phases were washed with a saturated aqueous NaCl solution (80 ml), dried (MgSO4) and concentrated. FC (SiO2, hexane/MTBE 30:1) of the crude product (5.5 g) gave (E)-1-(rel-(6R,7R)-7-methylspiro[4.5]decan-6-yl)but-2-en-1-one (1.6 g, 33%). Boiling point: 100° C. (0.07 mbar).

Provenance & Evidence