Explore advanced NMR techniques and electrophilic aromatic substitution in this 50-minute lecture from Yale University's Freshman Organic Chemistry II course. Delve into proton decoupling in C-13 NMR spectra and learn how dilute double labeling with C-13 confirmed complex steroid biosynthesis rearrangements. Discover the applications of two-dimensional NMR in protein structural determination and rapid carbocation rearrangement mechanism identification. Examine the two-step association-dissociation mechanism of electrophilic aromatic substitution, including the formation of cyclohexadienyl cation intermediates. Investigate how substituents influence product formation rates in substituted benzenes and explore the broad spectrum of electrophile reactivities. Learn about the significant contributions of Friedel and Crafts in Paris to electrophile activation. The lecture covers proton decoupling, C-13 NMR applications, 2-D NMR techniques, electrophilic aromatic substitution mechanisms, and historical contributions to the field. Read more