4-Methyl-5-vinylthiazole → (E)-methyl 2-(cyclohexyloxy)-8-(4-methylthiazol-5-yl)oct-7-enoate

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Reaction Conditions

Reaction Steps

A mixture of methyl 2-hydroxyoct-7-enoate (6.88 g, 0.040 mmol), dichloromethane (40 mL), 3,4-dihydro-2H-pyran (7.4 mL, 0.082 mol), and 6 drops of trifluoroacetic acid was stirred at room temperature overnight. The resulting mixture was concentrated in vacuo to yield methyl 2-(cyclohexyloxy)oct-7-enoate, which was used in the next step without further purification. A solution of methyl 2-(cyclohexyloxy)oct-7-enoate (500.0 mg, 1.95 mmol) dissolved in toluene (33 mL) containing 4-methyl-5-vinylthiazole (1.11 mL, 19.5 mmol) and Grubb's 2nd generation catalyst (166 mg, 0.195 mmol) was flushed with argon and heated in a sealed tube at 100° C. for 20 h. After cooling to room temperature, the solvent was removed in vacuo and the resulting residue was purified via flash silica gel chromatography (Analogix IF-280, SF25-115 g column, gradient 90:10-80:20 Heptane:EtOAc) to yield (E)-methyl 2-(cyclohexyloxy)-8-(4-methylthiazol-5-yl)oct-7-enoate. MS (ES+) 354 (M+1).

Provenance & Evidence