7.5 E2 Reactions | Organic Chemistry

Chad breaks down everything you need to know about E2 Reactions. He starts with the concerted mechanism and the rate law showing the E2 reaction mechanism stereochemistry, how the beta hydrogen and the leaving group must be antiperiplanar when E2 elimination occurs. He introduces Zaitsev Rule (aka Saytzeff Rule), how it is most common in E2 reactions for the most substituted alkene possible to be the major product. He then shows that for some substrates with only one beta hydrogen only one specific stereoisomer may be possible for the product (either E or Z) and shows how to predict which one it is. Chad then explains that for E2 reactions involving cyclohexane the beta hydrogen and the leaving group must be trans-diaxial in order to be antiperiplanar and for the E2 mechanism to occur. He concludes the lesson by showing common exceptions to Zaitsev rule (Hofmann Elimination) such as when a bulky base (like t-butoxide) is used or when having a poor leaving group like fluorine.

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00:00 Lesson Introduction
00:52 E2 Reaction Mechanism and Zaitsev Rule
02:41 E2 Rate Law
03:41 E2 Reaction Stereochemistry - Antiperiplanar
08:43 E2 Reactions Stereochemistry - E vs Z Alkene Product
14:14 E2 Reactions with Cyclohexane
19:10 E2 with a Bulky Base (Hofmann Product)
22:44 E2 with a Bad Leaving Group (Hofmann Product)

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