title: Synthesis of γ-, δ-, and ε-lactams by asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)iminoesters.
abstract: Highly enantiomerically enriched γ- and δ-lactams have been prepared by a simple and very efficient procedure that involves the asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)iminoesters followed by desulfinylation of the nitrogen atom and spontaneous cyclization to the desired lactams during the basic workup procedure. Five- and six-membered ring lactams bearing aromatic, heteroaromatic, and aliphatic substituents have been obtained in very high yields and ee's up to >99%. A slight modification of the procedure also allowed the preparation of ε-lactams in good yields and very high enantioselectivities. Both enantiomers of the final lactams could be prepared with equal efficiency by changing the absolute configuration of the sulfinyl chiral auxiliary.
authors.affiliation: Departamento de Química Orgánica, Facultad de Ciencias and Instituto de Síntesis Orgánica, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain. dguijarro@ua.es
authors.forename: David
authors.initials: D
authors.lastname: Guijarro
authors.forename: Óscar
authors.initials: Ó
authors.lastname: Pablo
authors.forename: Miguel
authors.initials: M
authors.lastname: Yus
mesh_terms: D003500:Cyclization; D006865:Hydrogenation; D007097:Imines / Q000737:chemistry*; D007769:Lactams / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D007097:Imines; D007769:Lactams; D013438:Sulfhydryl Compounds