CH ENGR 104C Lecture Notes - Lecture 10: Sn2 Reaction, Leaving Group, Pi Bond
7 Feb 2017
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Document Summary
What is a carbonyl group and what are its properties: a carbonyl is any compound that has a carbon double-bonded to an oxygen, carbonyls can behave as a nucleophile or an electrophile. Nucleophilic oxygen: electron-rich pi bond, lone pairs on oxygen, - charge on oxygen. Electrophilic carbon: + charge on carbon: - and + charges due to more electronegative oxygen (en=3. 4) compared to carbon (en=2. 5, geometry: trigonal planar, sp2 hybridized. Tip #1: protonation of oxygen end of carbonyl can only occur in presence of strong acid (i. e. h2so4, roh2+, h3o+) Tip #2: if there is strong acid present in a reaction, usually protonate the carbonyl first. 1: strong base deprotonates r group of carbonyl, yields enolate with new pi bond formed and negative charge on oxygen. Tip: although incorrect in terms of reasoning, this step can be better remembered by seeing that it is very similar to the carbocation fate step lose a proton, form a pi bond .
