4-Methoxybenzylamine → (3S)-3-[(1R)-1-(t-butyldimethylsilyloxy)ethyl]-1-(4-methoxybenzyl)azetidin-2-one

Participants

Reaction Steps

To a solution of ethyl (2-[1-(t-butyldimethyl-silyloxy)ethyl]acrylate (5 g) in methanol (100 ml) was added 4-methoxybenzylamine (2.65 g) at room temperature. After two days, the solvent was evaporated and the residual methanol was azeotropically removed using toluene. To the residual product was added tetrahydrofuran (387 ml) and the solution was stirred at room temperature. To this solution was added dropwise mesitylmagnesium bromide in tetrahydrofuran (1M, 31 ml) at room temperature. After stirring for 30 minutes, the reaction mixture was quenched with water and evaporated. The aqueous layer was 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 column-chromatographed on silica gel (eluent : a mixture of hexane and ethyl acetate, 3:1) to give (3S*)-3-[(1R*)-1-(t-butyldimethylsilyloxy)ethyl]-1-(4-methoxybenzyl)azetidin-2-one (4.5 g).

Provenance & Evidence