Ethyl 4-methylenecyclohexanecarboxylate

Triphenylmethylphosphonium bromide (53.7g, 0.15mol) was dissolved in 500mL of THF, and potassium tert-butoxide (16.8g, 0.15mol) was added at -20°C. Reacted for 0.5h after the temperature was raised to 0 °C. Subsequently, ethyl 4-oxo-cyclohexylcarboxylate (Compound 8-1) (17g, 0.1mol) was dissolved in 100mL of THF and added dropwise to the flask under nitrogen, reacted at room temperature for 3 hours, then a small amount of water was added to dissolve the solid, and rotary evaporated to remove THF, extracted with anhydrous diethyl ether, dried, and concentrated, the concentrate was dissolved in n-hexane, and filtered by silica gel, then concentrated to give Compound 8-2 as a colorless liquid (16.1g, 95.7percent yield).1) Example 6 Ethyl 4-meth lenecyclohexanecarboxylate19[0141] To a suspension of methyltriphenylphosphonium bromide (1.57 g, 4.41 mmol) in THF (9 mL) at -10 °C was added w-BuLi (2.5 M in hexanes, 1.65 mL, 4.11 mmol) dropwise and the solution was allowed to stir for lh. Ethyl 4-oxocyclohexanecarboxylate (0.47 mL, 2.94 mmol) was added and the reaction was allowed to warm to room temperature over 3 h. Acetone (3 mL) was added and the solvent was removed under reduced pressure. The residue was suspended in dichloromethane and ethyl ether (1 : 1), filtered and concentrated. The crude was purified by flash column chromatography to afford 19 as clear oil (419 mg, 85percent). H NMR: 1.25 (t, 3H), 1.50-1.70 (m, 2H), 1.90-2.16 (m, 4H), 2.30-2.50 (m, 3H), 4.12 (q, 2H), 4.65 (s, 2H).30A. Preparation of 4-Methylenecyclohexanecarboxylic acid ethyl ester; A suspension of methyl phosphonium bromide (3.15 g, 8.82 mmol) in dry THF (20 mL) was cooled to 0To a suspension of MePhLithium bis(trimethylsilyl)amide (1.0 M in THF, 15 mL, 15 mmol) was added dropwisely to a stirred solution of methyltriphenylphosphonium bromide (5.36 g, 15 mmol) in THF (50 mL) at 0 °C and stirred for 40 min at the same temperature. A solution of ethyl 4-oxocyclohexanecarboxylate (2.04 g, 12 mmol) in THF (20 mL) was added slowly at 0 °C and stirred for 2 h from 0 °C to room temperature. The reaction was quenched with saturated NHN-butyllithium (21 mL, 52.5 mmol) was added dropwise to a solution of diisopropylamine (7.54 mL, 52.9 mmol) in THF (40 mL) at -78° C. over a period of 10 min. Methyltriphenylphosphonium bromide (4.20 g, 11.75 mmol) and potassium 2-methylpropan-2-olate (1.32 g, 11.75 mmol) were dissolved in 1, 4-dioxane (20 mL) under nitrogen. The solution was stirred for 30 min then cooled to 0 °C. Separately, ethyl 4-methylenecyclohexane-1-carboxylate (1.06 g, 11.75 mmol) was dissolved in 1, 4-dioxane (5 mL) and added dropwise over 15 min. The reaction mixture was stirred at 20 °C for 1.5 h. The volatiles were removed under reduced pressure. The crude product was dissolved in DCM (30 mL) and filtered. The filtrate was purified via silica gel chromatography eluting with 0-40percent EtOAc in heptane to afford ethyl 4-methylenecyclohexane-1-carboxylate 26 (1.06 g, 54percent) as a clear oil. Brief procedure: KO-tBu was added to a solution of methyltriphenylphosponium bromide at 0 °C under nitrogen atmosphere and stirred for 30 min. To the above yellow colored reaction, a solution of ethyl 4-oxocyclohexane carboxylate in THF was added dropwise and the resulting mixture was stirred at the same temperature for 16 h. Work up: The reaction mixture was quenched with water and extracted with diethyl ether. The combined ethereal extract was dried and concentrated under reduced pressure. Purification: The crude residue was purified by silica gel (100-200 mesh) column chromatography by gradual elution from 5percent to 10percent EtOAc-petroleum ether. TLC system: 20percent Ethyl acetate-petroleum ether, RPotassium tert-butoxide (24 gm, 0.22 moles) and triphenylphosphine methyl iodide (78 gm, 28.22 moles) were dissolved in dry tetrahydrofuran (150 ml). The mixture was cooled to -78

Molecular Weight:168.23
XLogP3:1.9
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:3
Exact Mass:168.115029749
Monoisotopic Mass:168.115029749
Topological Polar Surface Area:26.3
Heavy Atom Count:12
Complexity:174
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes