Diisopropylamine → Tert-butyl 2-(2-allylcyclohexylidene)acetate

関与物質

反応条件

反応手順

To a solution of diisopropylamine (6.60 mL, 46.6 mmol) in THF (200 mL) at −10° C., was added a solution 2.22M of n-butyllithium (20.4 mL, 44.4 mmol). The solution was stirred 15 min at −10° C., cooled down to −78° C. and tert-butyl 2-trimethylsilylacetate (9.7 mL, 44.4 mmol) in 1 mL of THF was added dropwise. The solution was stirred 15 min at −78° C., and 2-allylcyclohexanone (3.3 mL, 22.2 mmol) was added dropwise. The reaction mixture was stirred 1 h at −78° C. and 3 h at −25° C. It was then quenched with saturated NH4Cl, extracted with ethylacetate, washed with brine, dried and concentrated. Purification by flash chromatography (cyclohexane) gave tert-butyl 2-(2-allylcyclohexylidene)acetate (5.06 g, 96%) as a colorless liquid. 1H NMR (400 MHz, CDCl3) 5.62 (1H, m), 5.41 (1H, s), 4.89 (2H, m), 3.83 (1H, m), 2.16 (3H, m), 1.90 (1H, m), 1.73 (1H, m), 1.61 (1H, m), 1.47-1.22 (4H, m), 1.36 (9H, s).

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