L-Glutamic acid 5-tert-butyl ester

In a 3000mL three-necked flask, 2324g of tert-butyl acetate and 73.5g of glutamic acid were added, stirred, and was added dropwise. 160.8 mL of perchloric acid, react for 48 hours at 10C, cool down to 0C, add 1000 mL of water, extract (the remaining tert-butyl acetate was used as solvent extraction), neutralized with Na2CO3 to pH=8 to 9, partitioned, and then extracted with 400 mL of 1% Na2CO3 aqueous solution was washed three times, and the tert-butyl acetate layer was concentrated under reduced pressure to give 42 g of Glu(OtBu)2 as an oil in 32.4% yield.

In a 1000 mL three-necked flask, 42 g of Glu(OtBu)2 was added, 400 mL of water and 11 g of CuCl2 were added, . The temperature was raised to 50 C and the reaction was carried out for 12 h to produce Cu[Glu(OtBu)]x (x=1-2); then it was lowered to room temperature and was added 19g tetramethylethylenediamine and 100mL dioxane, and then adjust the pH to 8~9 with triethylamine to produce L-glutamic acid-5-tert-butyl ester.