3,878 views
In this video, we discuss the Nucleophilic Aromatic Substitution (SNAr) reactions. These transformations can occur through three mechanisms. We begin by discussing the addition-elimination mechanism, talking about the need for electron-withdrawing substituent groups in ortho and/or para, and about the kinetic evidence that the addition step is the rate-determining one. Next, we discuss the elimination-addition mechanism, citing the isotopic labeling and kinetic isotope effect experiments that support the mechanism and the existence of the benzyne intermediate. Finally, we address the mechanism of unimolecular nucleophilic substitution in aromatic systems (SN1Ar), as well as its preparative importance as the Sandmeyer reaction. ---- Work licensed under https://creativecommons.org/licenses/... This video was prepared as part of the asynchronous follow-up material for the discipline “Organic Reaction Mechanisms”, of the Bachelor's Degree in Chemistry at the Federal University of ABC, for the emergency supplementary school period from September 21 to December 12, 2020. I hope it can be useful for other people as well, from students to those curious about Organic Chemistry. – FH Bartoloni ----