Скачать или смотреть Ozonolysis of Alkenes | Alkene + Ozone | Organic Reaction Mechanism | [4K] 009

#Alkenes #OxidativeCleavage #Ozonolysis #Molozonide #Ozonide #KetonesAndAldehydes #OrganicChemistry #ReactionMechanism #3dVisualization

0:13 Intro
0:44 Prediction of major product
1:34 Reaction Mechanism
1:48 *[Stage 1] Ozonide Formation (Cycloaddition and Rearrangement)
2:01 Stage 1_Step 1: Initial Cycloaddition (1,3-Dipolar Cycloaddition)
2:36 Stage 1_Step 2: Molozonide Rearrangement
3:03 Stage 1_Step 3: Formation of Ozonide (Secondary Cycloaddition)
3:48 [Stage 2] Reductive Work-up
4:01 **Stage 2_Step 4: Reductive Cleavage
5:12 [Replay Center] Mech-Viz
6:09 ***Comparison: Cleavage by KMnO₄
7:26 Summary
8:56 See you in the next Reaction~

Dive deep into the fascinating Ozonolysis reaction, a powerful method of oxidative cleavage used in organic chemistry to break carbon-carbon double bonds (C=C) and produce ketones and aldehydes. This comprehensive video breaks down the reaction mechanism of ozonolysis, explaining how 2-methylbut-2-ene is transformed into its final products.

We start by predicting the products—namely acetone and acetaldehyde—by simply imagining replacing the double bond with two C=O groups.

The Two-Stage Process: The video thoroughly explains the two conceptual stages:

1. Ozonide Formation: The highly reactive ozone (O₃) acts as a 1,3-dipolar species, leading to the formation of the highly unstable molozonide (a 1,2,3-trioxolane). This intermediate quickly rearranges through fragmentation (yielding a carbonyl compound and a carbonyl oxide, a zwitterion) to form the more stable ozonide (a 1,2,4-trioxolane). Crucially, we discuss the necessity of maintaining very low temperatures (e.g., -78°C) due to the ozonide's shock-sensitive nature.

2. Reductive Work-up: We detail how a reducing agent, such as dimethyl sulfide (DMS, 𝑀𝑒₂S), safely cleaves the ozonide intermediate to yield the desired final carbonyl products (ketones and aldehydes).

**Reaction Comparison and Advanced Topics:
Finally, we compare the reductive ozonolysis to other significant cleavage reactions, including treatment with hot, concentrated KMnO₄ and oxidative ozonolysis (using H₂O₂), highlighting how the choice of work-up agent dictates the final product's oxidation state (producing carboxylic acids instead of aldehydes).

This video is essential for students studying the transformation of alkenes and mastering reaction prediction and mechanism analysis.