Ethyl diazoacetate → Ethyl 2-chloro-2-fluorocyclopropanecarboxylate

Participants

Reaction Conditions

Reaction Steps

n-Heptane (38.3 g), 2,2′-isopropylidenebis[(4S)-4-tert-butyl-2-oxazoline] (162 mg, 0.55 mmol), and copper (II) trifluoromethanesulfonate (180 mg, 0.50 mmol) were added in in an autoclave, and then 1-chloro-1-fluoroethylene (40 g, 0.50 mol) was charged under elevated pressure. After the mixed solution was warmed to 30° C., a mixed solution containing 95% of ethyl diazoacetate (6.0 g, 50 mmol) and n-heptane (25 g) was charged under elevated pressure over five hours. n-Heptane (20 ml) was further charged under elevated pressure and stirring was continued at the same temperature for 1 hour, and then the internal pressure was released to obtain a solution of ethyl 2-chloro-2-fluorocyclopropanecarboxylate in n-heptane (90.0 g). The content of the ethyl 2-chloro-2-fluorocyclopropanecarboxylate was 3.73% (yield based on ethyl diazoacetate: 40.3%), and the ratio of cis-isomer/trans-isomer was 64.0/36.0. The optical purity of the cis-isomer was 98% e.e. (1S,2R), and the optical purity of the trans-isomer was 86% e.e. (1S,2S).

Provenance & Evidence