1,2-Dibromoethane → (2R,3S,5S)-5-((1S,3S)-3-Benzyloxymethyl-1-hydroxy-4-methyl-pentyl)-3-isopropyl-2-[4-methoxy-3-(3 methoxy-propoxy)-phenyl]pyrrolidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

Alternatively, A solution of 27 g of aldehyde 7 in 30 mL of tetrahydrofuran is added to a room-temperature solution of the Grignard reagent prepared by refluxing 20 g of ((S)-2-chloromethyl-3-methyl-butoxymethyl)-benzene with 3.2 g of magnesium in 120 mL of tetrahydrofuran containing 1.3 g of 1,2-dibromoethane for 4 h. The reaction is stirred for 1 h at room temperature, then 100 mL of 2 N sulfuric add is added. The mixture is stirred until the excess magnesium has dissolved, then the phases are separated and the organic phase washed with 50 mL of 12% sodium chloride solution. The organic phase is concentrated in vacuum to give e.g. 42.6 g of the crude alcohol 8 as an oil.

Provenance & Evidence