Bergman cyclization, enediyne synthesis

Konig, B. Changing the reactivity of enediynes by metal-ion coordination. Eur. J. Org. Client. 2000, 381-385 Basak, A. Mandal, S. Bag, S.S. Chelation control in Bergman cyclization. Synthesis and reactivity of enediynyl ligands. Chem. Rev. 2003, 103. 4077 094. 

Li Z, Song D, Zhi J, Hu A (2011) Synthesis of ultrathin ordtaed porous cartxm through Bergman cyclization of enediyne self-assembled mraiolayers on silica nanoparticles. J Phys ChemC 115(32) 15829-15833... 

The main use of this reaction is for the synthesis of bowl-shaped polycyclic aromatic hydrocarbons and fullerenes [325], Exploring the boundaries of these reactions resulted in the synthesis of compounds of different geometry, tt-electron structure, aromaticity, and with the presence of heteroatoms [324]. Various cross-conjugated enediynes exert anionic cycloaromatization to form fulvene and fulvalene anions and even heterocycles. In accordance with the concept of aromaticity, the anionic Bergman type cyclization is preferred to the classical Bergman cycloaromatization of linear enediynes. This anionic cyclization differs considerably from the classical Bergman cyclization and related cycliza-tions, as well as from other dianionic cyclizations [326]. 

Scheme 3.98 Synthesis of isooxazolidine- and isooxazoline-based enediynes 3.800 and 3.802 and study of their cyclization using DSC [26, 372a,bj. BC, Bergman cyclization.

Basak, A., Bag, S.S., Majumder, P.A., Das, A.K. and Bertolasi, V. (2004) Effect of remote trigonal carbons on the kinetics of Bergman cyclization synthesis and chemical reactivity of pyridazinedione-based enediynes. Journal of Organic Chemistry, 69(20), 6927-6930. 

Kim, C.-S., Diez, C., and RusseU, K.C., Tautomer-dependent Bergman cyclization of novel uracil-enediyne chimeras, Chem.-Eur. /., 6,1555, 2000 Kumarasinghe, E.S., Peterson, M.A., and Robins, M.J., Synthesis of 5,6-bis(alkyn-l-yl)pyrimidines and related nucleosides. Tetrahedron Lett., 41, 8741, 2000. 

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