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On the Conrotatory Ring Opening of 3-Carbomethoxycyclobutene Vis-À-Vis 3-Carbomethoxy-1,2-Benzocyclobutene and the Predominant Inward Opening of 3-Dimethylaminocarbonyl-1,2-Benzocyclobutene

preprint
submitted on 17.09.2018 and posted on 18.09.2018 by Veejendra Yadav, Dasari L V K Prasad, Arpita Yadav, Maddali L N Rao

The torquoselectivity of conrotatory ring opening of 3-carbomethoxycyclobutene is controlled by pC1C2→s*C3C4 and sC3C4→p*CO interactions in the transition state in a 4-electron process as opposed to only sC3C4→p*CO interaction in an apparently 8-electron event in 3-carbomethoxy-1,2-benzocyclobutene. The ring opening of 3-carbomethoxy-1,2-benzocyclobutene is sufficiently endothermic. We therefore argue that the reverse ring closing reaction is faster than the forward ring opening reaction and, thus, it establishes an equilibrium between the two and subsequently allows formation of the more stable species via outward ring opening reaction. Application of this argument to 3-dimethylaminocarbonyl-1,2-benzocyclobutene explains the predominantly observed inward opening.

History

Email Address of Submitting Author

vijendra@iitk.ac.in

Institution

Indian Institute of Technology Kanpur

Country

India

ORCID For Submitting Author

0000-0001-8294-0677

Declaration of Conflict of Interest

The authors declare no competing financial interest.

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