ethyl (2S*,3R*)-3-(t-butyldimethylsilyloxy)-2-(4-methoxybenzylaminomethyl)butanoate → (3S)-3-[(1R)-1-(t-butyldimethylsilyloxy)ethyl]-1-(4-methoxybenzyl)azetidin-2-one

Participants

Reaction Steps

To a solution of ethyl (2S,3R)-3-(t-butyldimethylsilyloxy)-2-(4-methoxybenzylaminomethyl)butanoate (7.91 g, crude) in tetrahydrofuran (200 ml) was added dropwise mesitylmagnesium bromide (29 ml) at room temperature. After stirring for 30 minutes, the mixture was quenched with 0.2N hydrochloric acid (250 ml) ethyl acetate (200 ml). The aqueous layer was separated and extracted twice with ethyl acetate. The combined organic layers were washed with 1N hydrochloric acid, saturated aqueous sodium hydrogencarbonate, water and an aqueous sodium chloride in turn, and then dried over magnesium sulfate. The resultant solution was evaporated, and the residue was purified by column-chromatography to give (3S)-3-[(1R)-1-(t-butyldimethylsilyloxy)ethyl]-1-(4-methoxybenzyl)azetidin-2-one (3.55 g).

Provenance & Evidence