355129-44-1Relevant academic research and scientific papers
Stereocontrolled formation of cephams from 1,3-O-ethylidene-L-erythritol
Borsuk, Katarzyna,Suwinska, Kinga,Chmielewski, Marek
, p. 979 - 981 (2007/10/03)
[2+2]Cycloaddition of chlorosulfonyl isocyanate to (Z)-1,3-O-ethylidene-2-O-propenyl-4-O-trityl-L-erythiritol proceeds with excellent stereoselectivity to afford the corresponding (R)-4′-alkoxy-azetidin-2-one which can transformed into 5-oxa-cepham by intramolecular alkylation of the β-lactam nitrogen atom. Cepham having the alternative (S) configuration at the bridgehead carbon atom can be achieved by another methodology based on alkylation of the nitrogen atom in 4-vinyloxy-azetidin-2-one by the suitably protected 1,3-ethylidene-L-erythritol followed by intramolecular displacement of the vinyloxy group.
