Download Resonance Stabilization of Organic Chemistry - Review Sheet | CHEM 238 and more Study notes Organic Chemistry in PDF only on Docsity! Review for Exam 1 CHEM 238a • Resonance Stabilization of Allylic Groups o Hetero vs. Homolytic bond cleavage (double vs. single barbed arrows) • Dienes and Polyenes o Isolated, conjugated, cumulated o Direct vs. conjugate addition o Dust off alkene addition reactions and be able to apply to dienes • Measures of Stability o Heats of Hydrogenation The higher the energy, the higher the energy stored in bonds, the less stable For hydrogentation of double bonds o Bond dissociation energies The less energy used to cleave the bond indicates a more stable product Useful for radicals o One to One comparisons Must be conscious of the products and their relationship to each other in a comparison • Diels-Alder Reactions o Diene vs. dienophile What type of substitution makes something a good diene or dienophile? o Electron Pushing for a Pericyclic reaction You must know the electron pushing sequence to rationally predict products • Aromaticity o The special stability conferred by an aromatic system o The requirements for aromaticity Planar, continuous p-orbital network with 4n+2 electrons o Understand the difference and basis for aromatic, non-aromatic and anti-aromatic Polygon in circle treatment of MOs o How to effect a one-fold reduction of benzene, conditions, restrictions o Special reactivity of the benzylic position • Electrophilic Aromatic Substitution o Substitution mechanism vs. addition for alkenes o Know your electrophiles Be able to identify the electrophile and conditions needed to prepare it. o Nitration, sulfonation, bromination o Friedel-Crafts Alkylation and Acylation Reagents, limitations, strategies, Clemmenson and Wolff-Kishner Reductions o Multiple substitutions Activating vs. deactivating (rate) Ortho/para directors vs. meta directors (regioselectivity) Strategies for multiple substitutions
