Ethyl chloroformate → HCID 59921282, compound

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Reaction Steps

tert-BuLi solution (1.7 M in pentane, 800 mL; 1.59 M in pentane, 2L; 4.5 mol total) was added via cannula over 135 minutes under nitrogen into a solution of 1-Bromo-6-isopropyl-3-(2-methoxyvinyl)benzene (C) (500 g, 1.96 mol) in anhydrous THF (3 L) at −50 to −75° C. The mixture was stirred for 1 hour after addition was complete. The solution was then transferred via cannula into a chilled (kept below −50° C.) solution of ethyl chloroformate (562 mL, 5.88 moles) in anhydrous THF (2 L), and the resultant solution was stirred for 68 minutes. The reaction was quenched by addition of 1 L of saturated aqueous NH4Cl with stirring, followed by the addition of 2 L of water. The organic phase was separated, washed with a 10% NaCl solution. The solution was concentrated under vacuum to approximately. Evaporation furnished the crude product as a light yellow or greenish yellow liquid. A total of 3 batches were produced according to the above procedures, and 1.7 kg of crude product was obtained. The crude liquid product was distilled under high vacuum (0.9 mm Hg) and distillates in the range of 158 to 165° C. were collected to obtain 1075 g (yield 73%) of product. The following values were obtained by nuclear magnetic resonance spectroscopy:

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