Orientation in disubstituted benzenes
(b) When two groups the same time work against one another, the stronger one wins.
In this example, the methyl group directs o/p, but the methoxy group is a stronger activator and o/p director, so the OCH3 determines the position of substitution (see stronger green arrows):
(c) When two groups of different types work against one another, usually the activator wins out over the deactivator:
In this case, the OH group directs to three places; however substitution between two substituents is sterically hindered, so it tends to be a minor process (smaller green arrow). For this reason, only the two major products are shown.
- John D. Robert and Marjorie C.Caserio (1977) Basic Principles of Organic Chemistry, second edition. W. A. Benjamin, Inc. , Menlo Park, CA. ISBN 0-8053-8329-8. This content is copyrighted under the following conditions, “You are granted permission for individual, educational, research and non-commercial reproduction, distribution, display and performance of this work in any format.”
- L.G. Wade, “Organic Chemistry”, 6th edition. Prentice-Hall, 2005, ISBN 9780131478718.
- 22.6: Orientation in Disubstituted Benzenes. Authored by: John D. Robert and Marjorie C. Caserio. Located at: https://chem.libretexts.org/Textbook_Maps/Organic_Chemistry/Book%3A_Basic_Principles_of_Organic_Chemistry_(Roberts_and_Caserio)/22%3A_Arenes%2C_Electrophilic_Aromatic_Substitution/22.06%3A_Orientation_in_Disubstituted_Benzenes. Project: Chemistry LibreTexts . License: CC BY-NC-SA: Attribution-NonCommercial-ShareAlike