Lewis acid-promoted intermolecular carbonyl-ene reaction of enantiopure 4-oxoazetidine-2-carbaldehydes. Rapid entry to novel fused polycyclic beta-lactams.
Lewis acid-promoted carbonyl-ene reaction of enantiomerically pure 4-oxoazetidine-2-carbaldehydes with various activated alkenes gives 4-[(1'-hydroxy)homoallyl]-beta-lactams with a very high level of syn diastereofacial selectivity. The above homoallylic alcohols are used for the diastereoselective preparation of fused bicyclic, tricyclic, and tetracyclic beta-lactams of nonconventional structure using tandem one-pot radical addition/cyclization or elimination-intramolecular Diels-Alder sequences. In addition, a novel domino process was discovered, the C4-N1 beta-lactam bond breakage/intramolecular Diels-Alder reaction.
Alcaide
Benito
B
Departamento de Química Orgánica I, Facultad de Química, Universidad Complutense de Madrid, 28040 Madrid, Spain. alcaideb@quim.ucm.es
Almendros
Pedro
P
Pardo
Carmen
C
Rodríguez-Ranera
Carolina
C
Rodríguez-Vicente
Alberto
A