1,1-Dimethylethyl N-((1S)-2-(methoxymethylamino)-2-oxo-1-(phenylmethyl)ethyl)carbamate → tert-butyl N-[(2S)-1-oxo-3-phenylpropan-2-yl]carbamate

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Reaction Steps

A solution of N-(tert-butyloxy-carbonyl)-L-phenylalanine N,O-dimethylhydroxylamide (70.05g, 0.229 mol) in 1400 ml of anhydrous ether was cooled in an ice bath while under a nitrogen atmosphere. To this solution was added lithium aluminum hydride (10.88 g) 0.287 mol) as fast as possible while keeping the reaction under control. The ice bath was removed and the mixture was stirred for 30 minutes where upon it was quenched by addition of 1600 mL of aqueous solution containing 62.11 g of potassium bisulfate. The resulting mixture was stirred for 15 minutes and then was filtered through celite. The phases of the filtrate were separated and the aqueous phase was extracted with ether (2×300ml ). The combined ether layers were then extracted with 1N hydrochloric acid (2×1600ml ), saturated aqueous sodium bicarbonate (2×1600ml ) and saturated aqueous sodium chloride (300mL ). Resulting ether solution was then dried over MgSO4 and solvent was removed under vacuum to give a colorless oil 53.1 g which solidified on standing. The NMR shows about 60% aldehyde. This was used without further purification.

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