Soluble-Polymer-Supported Synthesis of β-Lactams on a Modified Poly(ethylene glycol)

✍ Scribed by Rita Annunziata; Maurizio Benaglia; Mauro Cinquini; Franco Cozzi

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 156 KB
• Volume: 6
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/(sici)1521-3765(20000103)6:1<133::aid-chem133>3.0.co;2-h

✦ Synopsis

A modified poly(ethylene glycol) (PEG) has been developed for the soluble-polymer-supported synthesis of b-lactams. The monomethylether of PEG (MeOPEG) with an average M W of 5000 was used as the support, a 4-(3propyl)phenyl residue as the spacer, and a 4-oxyphenylamino group as the moiety with the reactive functionality. From this modified PEG representative aromatic, heteroaromatic, unsaturated, and ali-phatic imines were obtained in high yields by different procedures. The polymer-supported imines were then employed to prepare several b-lactams by enolate/imine condensation and ketene/ imine cycloaddition. Examples of the control of the absolute stereochemistry during the azetidinone ring formation are also reported. The reactions carried out on the polymer-bound imines showed a remarkable similarity to those performed on nonimmobilized imines, both in terms of yields and stereoselectivities. Removal of the b-lactams from the polymer has also been accomplished to directly deliver the N-unsubstituted azetidinones.