Low and high temperature bromination of 2,3-dicarbomethoxy and 2,3-dicyano benzobarrelene: unexpected substituent effect on bromination†
Sara Taşkesenlioğlu,Arif Daştan,Erdin Dalkılıç,Murat Güney,Rza Abbasoğlu
New Journal of Chemistry Pub Date : 11/02/2009 00:00:00 , DOI:10.1039/B9NJ00372J
Abstract

The bromination of 2,3-dicarbomethoxy benzobarrelene yielded the dibromide regio- and stereospecifically arising from the aryl shift where the bromine exclusively attacks the double bond from the exo face of the double bond. High temperature bromination of this compound yielded aryl-shift products. From the low temperature bromination of 2,3-dicyano benzobarrelene, non-rearranged products were obtained along with the rearranged products. Surprisingly, we observed that the yield of non-rearranged products decreased on increasing the temperature. A possible role of the substituent was discussed using DFT calculations on model compounds.

Graphical abstract: Low and high temperature bromination of 2,3-dicarbomethoxy and 2,3-dicyano benzobarrelene: unexpected substituent effect on bromination