New synthesis of fused tricyclic 2-azetidinones using stereoselective allylation of cis-4-formyl-β-lactams and intramolecular diels-alder reaction

Article abstract of DOI:10.1016/S0040-4039(98)02513-1

Tin(IV) chloride promoted addition of allyltrimethylsilane to cis-4- formyl-2azetidinones 1 gives 4-[(1'-hydroxy)homoallyl]-β-lactams 2 with excellent stereoselectivities. The mesylates of alcohols 2 are used for the diastereoselective preparation of both 4-butadienyl-2-azetidinones 6 and fused tricyclic β-lactams 3 through a tandem one-pot eliminationintramolecular Diels-Alder reaction.