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Soluble‐Polymer‐Supported Synthesis of β ‐Lactams on a Modified Poly(ethylene glycol)
Author(s) -
Annunziata Rita,
Benaglia Maurizio,
Cinquini Mauro,
Cozzi Franco
Publication year - 2000
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/(sici)1521-3765(20000103)6:1<133::aid-chem133>3.0.co;2-h
Subject(s) - moiety , imine , chemistry , ethylene glycol , peg ratio , polymer , residue (chemistry) , cycloaddition , ketene , polymer chemistry , condensation reaction , ethylene , combinatorial chemistry , organic chemistry , catalysis , finance , economics
A modified poly(ethylene glycol) (PEG) has been developed for the soluble‐polymer‐supported synthesis of β ‐lactams. The monomethylether of PEG (MeOPEG) with an average M W of 5000 was used as the support, a 4‐(3‐propyl)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 aliphatic imines were obtained in high yields by different procedures. The polymer‐supported imines were then employed to prepare several β ‐lactams by enolate/enolate condensation and ketene/ketene 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 β ‐lactams from the polymer has also been accomplished to directly deliver the N ‐unsubstituted azetidinones.