Organic Molecular Mechanisms
Why Mechanisms Matter in Organic Chemistry
Thinking in Electron Flow
Organic reactions are best understood as movements of electron pairs and changes in bonding. Curved-arrow notation tracks nucleophiles, electrophiles, leaving groups, and intermediates.
Core Reactivity Terms
In an reaction, what happens in the key step?
An reaction is concerted, with backside attack and leaving group departure at the same time.
Correct answer: Bond formation and bond breaking occur simultaneously
What is the role of a leaving group?
A good leaving group stabilizes the electrons it takes upon departure.
Correct answer: to depart with the bonding electron pair
Substitution and Elimination Competition
Factors That Steer Outcomes
Substitution and elimination compete depending on substrate structure, base strength, solvent, and temperature. Strong base and heat often favor elimination, while good nucleophiles and less hindered substrates favor substitution.
Which condition often favors elimination over substitution?
Heat and strong base commonly promote elimination pathways.
Correct answer: High temperature and strong base
Name one factor that can increase elimination relative to substitution.
Raising temperature often favors elimination because it increases the entropic contribution.
Correct answer: higher temperature