109616-59-3

Upstream product

• 76899-07-5 (3R,4R)-3-[(R)-1-(tert-butyldimethylsilyloxy)ethyl]-4-acetoxyazetidin-2-one 
• 192864-91-8 (4S)-4-benzyl-3-(2-bromopropanoyl)-1,3-oxazolidin-2-one 
• 90719-32-7 (S)-4-Benzyl-2-oxazolidinone 

Downstream Products

• 96035-98-2 (3S,4S)-4-<(1S)-1-benzyloxycarbonylethyl>-3-<(1R)-1-tert-butyldimethylsilyloxyethyl>-2-azetidinone 

Relevant academic research and scientific papers

Highly stereocontrolled synthesis of the 1β-methylcarbapenem key intermediate by the Reformatsky reaction of 3-(2-bromopropionyl)-2-oxazolidone derivatives with a 4-acetoxy-2-azetidinone

The key synthetic intermediate (4) of 1β-methylcarbapenems (1~3) was efficiently synthesized by employing highly stereocontrolled Reformatsky reaction (C4-alkylation) of 3-(2-bromopropionyl)-2-oxazolidone derivatives (6) with (3R,4R)-4-acetoxy-3-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-2-azetidino ne (5) in the presence of zinc dust followed by removal of 2-oxazolidone moieties. The best diastereoselectivity (β:α = 95:5) could be realized by uses of sterically crowded achiral 2-oxazolidone derivatives such as 4,4-dimethyl-, 4,4,5,5-tetramethyl, and 4,4-dibutyl-5,5-pentamethylene-2-oxazolidone and higher reaction temperatures (refluxing tetrahydrofran). The remarkable diastereoselectivities observed for the Reformatsky reactions could be explained by means of the weakly chelating transition state models.