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Unformatted text preview: CHEMISTRY 3B Professor Peter Vollhardt 9/18/08 Lecture 7 ASUC Lecture Notes Online is the only authorized note-taking service at UC Berkeley. Do not share, copy or illegally distribute (electronically or otherwise) these notes. Our student-run program depends on your individual subscription for its continued existence. These notes are copyrighted by the University of California and are for your personal use only. D O N O T C O P Y Sharing or copying these notes is illegal and could end note taking for this course. LECTURE CHAPTER 15 (CONTINUED) Summary of Substituent Effects As a summary, you should have the above directors memorized. In other words, know all effects of substituents in electrophilic aromatic substitutions, whether they are ortho/para directors or meta/directors, and whether they are strong or weak activators or deactivators. Summary of Relative Rates Summary of Relative Rates Summary of Relative Rates NHAc NHAc ~ 10 ~ 10 6 6 20 20 < 0.1 80 < 0.1 80 Ph Ph 15 15 20 20 < 0.6 80 < 0.6 80 As you increase substitution of benzene, the substituent effects are additive. In other words, you will need to add up the directors of all substituents to determine which carbon sites will be most reactive. Guideline 1: The strongest activator wins The most powerful activator controls the position of attack: Above, both OH and CH3 direct ortho/para....
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- Fall '08
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