jo0614689_si_002.cif (30.2 kB)

Synthesis of Highly Functionalized Macrocycles by the Peripheral Functionalization of Macrocyclic Diimines

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posted on 10.11.2006, 00:00 by Miguel A. Sierra, Daniel Pellico, Mar Gómez-Gallego, María José Mancheño, Rosario Torres
The easily available macrocyclic diimines 47 can be stereoselectively transformed to macrocyclic bis-β-amino acids 1317, macrocyclic bisazetidines 1820, and macrocyclic bisamides 21 and 22 by means of the corresponding bis-β-lactam scaffolds 812. 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-β-lactams 812 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 57 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.