Chemistry
Stereochemistry of SN1 and SN2 Reactions
Quick fact
In an SN2 reaction, the nucleophile attacks from the back side, causing a complete inversion of configuration—like an umbrella turning inside out. In contrast, an SN1 reaction forms a flat carbocation intermediate, so the product is a roughly 50:50 mixture of both enantiomers, called a racemic mixture.
Why this is interesting
Imagine two molecules that are mirror images of each other. When you run a substitution reaction, does the product look like the starting material, its mirror image, or a mix of both? The answer depends on which mechanism—SN1 or SN2—is in play.