title: Synthesis of highly functionalized macrocycles by the peripheral functionalization of macrocyclic diimines.
abstract: The easily available macrocyclic diimines 4-7 can be stereoselectively transformed to macrocyclic bis-beta-amino acids 13-17, macrocyclic bisazetidines 18-20, and macrocyclic bisamides 21 and 22 by means of the corresponding bis-beta-lactam scaffolds 8-12. These key intermediates are available through standard Staudinger reaction and obtained as the cis-cis diastereomers, exclusively. An interesting relation between the proximity of the reactive C=N bonds and the selectivity in the formation of the bis-beta-lactams 8-12 is observed. Thus, diimine 4 leads to low selectivities, producing a 1:1 mixture of cis-syn-cis and cis-anti-cis diastereomers, while diimines 5-7 having the diimine sites more separated lead almost exclusively to the cis-anti-cis diastereomers. The stereochemistry of all the products was unambiguously assigned by X-ray diffraction analysis of compounds cis-syn-cis 8 and cis-anti-cis 12-Co2CO6 complex.
authors.affiliation: Departamento de Química Organica and Laboratorio de Difracción de Rayos X, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain. sierraor@quim.ucm.es
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Sierra
authors.forename: Daniel
authors.initials: D
authors.lastname: Pellico
authors.forename: Mar
authors.initials: M
authors.lastname: Gómez-Gallego
authors.forename: María José
authors.initials: MJ
authors.lastname: Mancheño
authors.forename: Rosario
authors.initials: R
authors.lastname: Torres