CORE Metadata, citation and similar papers at core.ac.uk Provided by Digital.CSIC Organocatalyzed Three-Component Ugi and Passerini Reactions of 4-Oxoazetidine-2- carbaldehydes and Azetidine-2,3-diones. Application to the Synthesis of -Lactams and -Lactones Benito Alcaide,*, † Pedro Almendros,‡ Cristina Aragoncillo,† Ricardo Callejo,† and M. Pilar Ruiz† †Grupo de Lactamas y Heterociclos Bioactivos, Departamento de Química Orgánica I, Unidad Asociada al CSIC, Facultad de Química, Universidad Complutense de Madrid, 28040-Madrid, Spain, ‡Instituto de Química Orgánica General, IQOG, CSIC, Juan de la Cierva 3, 28006-Madrid, Spain, and
[email protected] ABSTRACT X 2 1 H H 2 H H "ring-opening" R NHR R2 CHO "U-3CR" R NHR 3 "P-3CR" "cyclization" NHR 3 N O O N PhP(OH)2 (cat.) 1 X O R1 O R O 1 4 4 4 2 for: R NH2, X = NHR 6 X = NR 3 for: H2O, X = OH 7 X = O O O O O O H O HO H "P-3CR" 2 N PhP(OH) (cat.) R HN 1 2 N O R O R1 4 syn-5 Organocatalyzed U-3CR of 4-oxoazetidine-2-carbaldehydes has been studied. Besides, it the organocatalyzed P-3CR of 4-oxoazetidine-2-carbaldehydes and azetidine-2,3-diones has been described for the first time. U-3CR and P-3CR adducts have been obtained in good yields and reasonable diastereoselectivities. Phenyl phosphinic acid has been the catalyst of choice to study the scope of both organocatalyzed multicomponent reactions using a variety of -lactams, isocyanides and amines.