87661-20-9

865-47-4

4023-34-1

87661-20-9

219.1 g (1913 mmol, 1 eq.) of potassium tert-butoxide was suspended in 2.5 L of tert-butyl methyl ether and the mixture was cooled to 0-5 °C. 200 g (1913 mmol, 1 eq.) of cyclopropanecarbonyl chloride was added slowly and dropwise over 60 min while maintaining the reaction temperature between 0-5 °C (cooled using an ice-ethanol bath). The progress of the reaction was monitored by on-line FTIR to ensure that the reaction was carried out in a controlled manner. The reaction mixture was continued to be stirred at 0-5 °C for 30 min before being neutralized by adding 1 L of 5% aqueous sodium bicarbonate solution. The aqueous phase was separated and the aqueous phase was extracted with 500 mL of tert-butyl methyl ether. The organic phase was combined and washed with 500 mL of half-saturated aqueous sodium chloride solution. The organic phase was concentrated under reduced pressure (30 °C/150 mbar) to give 271 g of tert-butyl cyclopropanecarboxylate (91% yield, containing 8% residual tert-butyl methyl ether).