Into a 25-mL round-bottom flask purged and maintained with an inert atmosphere of nitrogen was placed ethyl 3,5-dichloro-1,2-thiazole-4-carboxylate (150 mg, 0.66 mmol, 1.00 equiv), (4-methylcyclohex-1-en-1-yl)boronic acid (103 mg, 0.74 mmol, 1.11 equiv), Pd(PPh3)4 (38 mg, 0.03 mmol, 0.05 equiv), K3PO4 (368 mg, 1.73 mmol, 2.61 equiv), dioxane (3 mL). The resulting solution was stirred overnight at 90° C. in an oil bath. The solids were removed by filtration. The resulting mixture was concentrated under reduced pressure. The residue was applied to a silica gel column, eluting with ethyl acetate/petroleum ether (2:98) to afford 120 mg (63%) of ethyl 3-chloro-5-(4-methylcyclohex-1-en-1-yl)-1,2-thiazole-4-carboxylate as a colorless oil.
