CHM 2120 Study Guide - Midterm Guide: Chemical Shift, Phenyl Group, Benzene

• School: University of Ottawa
• Department: Chemistry
• Course: CHM 2120
• Professor: Alison Flynn

Document Summary

Chemical shift ppm shielded if surrounded by edg (atom has high electron density) alkyl groups surrounding. Low ppm de-shielded if surrounded by ewg (atom have low electron density) Common proton chemical shifts next to c=o : 2. 1-2. 5 next to -o- : 3-5 next to benzene: 6. 5-8 on aldehyde: 9-10 on carboxylic acid: 11-12 acidic protons have highly variable chemical shifts. Nbs / roor bromination occurs at 1 carbon away from the double bonded carbon. H- alone is strong base, but bad nu. Carbonyl chemistry addition of nu on carbonyl bearing heteroatom. Rate determining step: formation of tetrahedral intermediate (ti) Molecular orbitals electrons in homo of nu overlap with pi* orbital of c in c=o (lumo) energy between homo of nu and lumo of c=o determines speed of reaction large = slow small = fast rate determining step. Relative reactivities of carboxylic acid derivatives (hi to low)