title: Three-step metal-promoted allene-based preparation of bis(heterocyclic) cyclophanes from carbonyl compounds.
abstract: A straightforward metal-mediated method for the synthesis of bis(dihydrofuryl) cyclophane scaffolds from carbonyl compounds has been developed. The combination of the dihydrofuran moiety with different heterocycles such as β-lactams and sugars allows high levels of skeletal diversity. The process comprises indium-promoted one-pot carbonyl bis(allenylation) and gold- or palladium-catalyzed double cyclization in the resulting bis(allenols), followed by selective ruthenium-catalyzed macrocyclization. In some cases, the method has been successfully applied to the synthesis of the challenging Z-isomers. The E- versus Z-stereochemistry of the metathesis-formed double bonds could not be assigned taking into consideration the usual coupling constants criteria, but a diagnostic based on the chemical shifts of the two olefinic protons located at the macrocyclic double bond was established.
authors.affiliation: 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.
authors.forename: Benito
authors.initials: B
authors.lastname: Alcaide
authors.forename: Pedro
authors.initials: P
authors.lastname: Almendros
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Quirós
authors.forename: Carlos
authors.initials: C
authors.lastname: Lázaro
authors.forename: M Rosario
authors.initials: MR
authors.lastname: Torres
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D004988:Ethers, Cyclic / Q000138:chemical synthesis* / Q000737:chemistry; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D047028:Macrocyclic Compounds / Q000737:chemistry*; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*; D011522:Protons; D012428:Ruthenium / Q000737:chemistry*; D013237:Stereoisomerism; D047090:beta-Lactams / Q000138:chemical synthesis* / Q000737:chemistry; D000097566:Cyclophanes
chemical_list: D000475:Alkenes; D004988:Ethers, Cyclic; D005663:Furans; D006046:Gold; D047028:Macrocyclic Compounds; D010165:Palladium; D011522:Protons; D012428:Ruthenium; D047090:beta-Lactams; C000593327:bis(dihydrofuryl)cyclophane; D000097566:Cyclophanes