Highly stereocontrolled synthesis of the 1β-methylcarbapenem key intermediate by the reformatsky reaction of 3-(2-bromopropionyl)-2-oxazolidone derivatives with a …
Y Ito, A Sasaki, K Tamoto, M Sunagawa, S Terashima
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) ethylJ-2-azetidinone (5) in the presence of zinc dust followed by removal of 2-oxazolidone moieties. The best diastereoselectivity (β: α= 95: 5) could be ...