CHEM102 Lecture 12: Alkyl Halides
Document Summary
Nuleophilic substitution of alkyl halides: general mechanism of a substitution reaction. If the starting alkyl halide has a chiral carbon adjacent to x then the sn2 reaction occurs with inversion of stereochemistry. Cannot undergo sn1 as a primary carbocation is too unstable. Also little steric hindrance to direct nucleophilic attack: secondary alkyl halides, can undergo sn2 or sn1, a poor neutral nucleophile and a polar solvent e. g water favours sn1. The more substituted the alkene the more thermodynamically stable it is. Reactions of alcohols alkoxides: less hydrogen bonding. Reactions of alcohols conversion to alkyl halides: see lecture notes. Basicity of alcohols dehydration under acidic conditions to give alkenes: hbr is more acidic than water, to get alcohols to eliminate, treat with water it will protonate acid and water will be removed. Acidity of alcohols and phenols: lower pka = more acidic.
