Sodium hydride → (Rac)-4-[3-(tert-butyl-dimethyl-silanyloxy)-1-methoxycarbonyl-propyl]-5-oxo-[1,4]diazepane-1-carboxylic acid benzyl ester

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Reaction Steps

A solution of 6.95 g (28.0 mmol) of 5-oxo-[1,4]diazepane-1-carboxylic acid benzyl ester in 85 ml of N,N-dimethylformamide was treated at 0° C. with 1.47 g (33.6 mmol) of NaH (55% in oil) in three portions. After 30 min, 10.0 g (28.0 mmol) of (rac)-4-(tert-butyl-dimethyl-silanyloxy)-2-iodo-butyric acid methyl ester (intermediate 1) were added during 5 min. The solution was stirred 2¼ h at 0° C. and neutralized with cold 10% aq. potassium hydrogensulfate solution and extracted with diethyl ether (3×). The organic phases were washed with sat. aq. sodium hydrogencarbonate solution, 10% aq. sodium chloride solution, dried over Na2SO4 evaporated and purified by flash silica gel column (n-heptane/ethyl acetate 4:1 to 2:1) to yield 8.45 g (63%) of the title compound as yellow viscous oil. MS: 479.2 (MH+).

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