Enediyne crown ethers

Konig, B. Rutters, H. Synthesis and reactivity of the first bis(crown ether) enediyne. Tetrahedron Lett. 1994, 35, 3501-3504. 

McPhee, M.M. Kerwin, S.M. Synthesis and metal ion binding studies of enediyne-containing crown ethers. J. Org. Chem. 1996, 61, 9385-9393. 

The thermal properties of the benzo-crown enediynes esters and their complexes were studied by DSC [397]. In the absence of a hydrogen donor, the radicals polymerized evolving heat, which gave an exothermic peak in the DSC curve. The onset temperature of the exothermic peak corresponds to the temperature required for Bergman cyclization confirming the generation of free radicals. For the crown ether derivative 3.495 and its complexes 3.496 and 3.876, this temperature was... 

An alternative approach to the antitumor active enediyne systems (cf. eq 47) using Nicholas cations has been extensively studied and applied to the dynemycin core structure (eq 53). Another example of the use of such cations in forming strained rings is the preparation of a cobalt complex of a trithia-crown ether (eq 54), which has been shown to complex Cu and Ag ... 

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