A QUANTUM CHEMICAL STUDY OF THE MECHANISM OF THE REGIOSELECTIVE DOMINO-REACTION OF O-VINYL-2-TETRALONE OXIME
V. A. Shagun, A. M. Vasil’tsov, A. V. Ivanov, A. I. Mikhaleva, B. A. Trofimov
Keywords: O-vinyl oxime, indole, quantum chemical calculation, reaction mechanism, sin-(Z)/anti-(E)-isomerization
Abstract
Quantum chemical (DFT) methods are used to study the mechanisms of intramolecular rearrangements (domino-transformations) in O-vinyl-2-tetralone oxime, which potentially can produce both conjugated and non-conjugated dihydrobenzindoles. Transition states of elementary reaction steps are localized. The 1,3-prototropic shift promoted by a mediator molecule (Н2О) is the limiting step. An activation barrier of the formation of conjugated indole is 4.14 kcal/mol lower than the formation channel on the non-conjugated analog. Activation barriers of syn-(Z)/anti-(E)-isomerization in O-vinyl-2-tetralone oxime are analyzed. It is shown that with regard to barriers of the promoted prototropic shift, Z/E-isomerization is a rapid process.
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