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Metal directed stereoselective synthesis of 3-(1′-hydroxyethyl)-2-azetidinones from ethyl 3-hydroxybutyrate

✍ Scribed by Gunda I. Georg; Eyüp Akgün

Publisher: Elsevier Science
Year: 1990
Tongue: French
Weight: 251 KB
Volume: 31
Category: Article
ISSN: 0040-4039
DOI: 10.1016/s0040-4039(00)89040-1

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✦ Synopsis

The enolate-imine condensation of the lithio dianion 8 of ethyl 3-hydroxybutyrate 7 with Nanisylcinnamylideneimine was studied in the presence of a variety of metal salts and organometallic reagents. Addition of terr-butyl magnesium chloride to the reaction mixture produced the reZ(l'R,3R,4S)-3-(l'-#mxyethyl)-2-azettdmone 9, whereas the addition of triethylborane gave solely the rel(l'R,3R,4R) derivative 3-(l'-Hydroxyethyl)-2-azetidinones of type 1, possessing the depicted absolute stereochemistry at the three contiguous chiral centers, are important building blocks for the asymmetric synthesis of potent P-lactam antibiotics' such as derivatives of thienamycin 2 and 1-g-methylthienamycin 3, the olivanic acids, the penems.

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