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The Effect of Charge‐Transfer Complexation/π‐Stacking Interactions in Lowering the Activation Barrier of the Bergman Cyclization
Author(s) -
Basak Amit,
Bag Subhendu Sekhar,
Das Amit K.
Publication year - 2005
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200400660
Subject(s) - chemistry , acceptor , stacking , reactivity (psychology) , intramolecular force , charge (physics) , photochemistry , computational chemistry , stereochemistry , organic chemistry , medicine , physics , alternative medicine , pathology , quantum mechanics , condensed matter physics
To elaborate the concept of weak interactions and their effect on Bergman Cyclization (BC), several 1,2‐dikynyl benzenes incorporating various combinations of donor and acceptor units in the two arms of the enediynes were designed and synthesized, and their charge‐transfer interactions followed by UV/Vis spectroscopy. The thermal reactivities, as studied by DSC, show an increase in reactivity for the donor/acceptor or donor/donor combinations relative to the acceptor/acceptor pair. Such an increase in reactivity can be explained on the basis of intramolecular charge transfer and π‐stacking interactions between the two arms, which may lower the distance between the two acetylenic ends. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)