Hydrochloric Acid → (2S,3R)-1-(tert-butyldimethylsilyl)-3-methyl-4-oxoazetidine-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of 27.5 ml of diisopropylamine in 150 ml of THF at -20° C. was added 73.5 ml of 2.4N n-butyl lithium in hexane. After 15 minutes, the solution was cooled to -70° C. and a solution of 20 gm of (4S)-1-t-butyldimethylsilylazetidin-2-one-4-carboxylic acid in 75 mL of THF was added. The solution was warmed to -20° C. for 15 minutes before a solution of 13.5 mL of methyl iodide in 20 mL of THF was added. After 30 minutes at -20° to 0° C., the reaction was diluted with 300 mL of ether and then poured into a mixture of ice and 400 mL of 1N HCl. The layers were separated and the aqueous layer extracted with ether. The ether layers were washed with brine, dried over sodium sulfate and evaporated. The residue was crystallized from hexane to give 12-15 gms of (3R,4S)-1-t-butyldimethylsilyl-3-methylazetidin-2-one-4-carboxylic acid.

Provenance & Evidence