Abstract
The substituted-9-bromo-9,10-dihydro-9,10-ethanoanthracenes ortho 8a-12a and meta 8b-13b have been synthesized via Diels-Alder reaction under microwave conditions. The cycloadduct isomers ortho 8a-11a and meta 8b-11b, with priority to ortho 8a-11a, were obtained from the reaction of 9-bromoanthracene 1 with acrylonitrile 2, 2-chloroacrylonitrile 3, methacryloyl chloride 4 and acrylic acid 5, while ortho 12a and meta 12b, with priority to meta 12b, was obtained from the reaction of 9-bromoanthracene 1 with 1-cynao vinyl acetate 6. Interestingly, the only isomer meta 13b was obtained from the reaction of 9-bromoanthracene 1 with phenyl vinyl sulfone 7. The results proved that the steric or/and electronic nature of the dienophile substituent is/are playing significant roles in the regioselectivity and isomers ratio. (c) 2020 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).