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).

[1] Patent: US2009/23713, 2009, A1. Location in patent: Page/Page column 20
[2] Patent: US2010/22518, 2010, A1. Location in patent: Page/Page column 20
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[4] Patent: US2011/92698, 2011, A1. Location in patent: Page/Page column 22
[5] Journal of Organic Chemistry, 2009, vol. 74, # 22, p. 8726 - 8732