Draw a stepwise mechanism for the following reaction. |...

Name: Problem 45, Chapter 16: Organic Chemistry
Uploaded: 2019-11-15T06:13:40-08:00
Duration: 5 min 57 s
Channel: Ian Kaigh
Description: Draw a stepwise mechanism for the following reaction.

Key Concepts

Stepwise Reaction Mechanism

A stepwise reaction mechanism breaks down an overall reaction into a series of distinct elementary steps. Each individual step represents a separate process that contributes to the overall transformation, often involving the formation and subsequent reactions of intermediate species. This concept is central to understanding how complex reactions progress at the molecular level.

Reaction Intermediates

Reaction intermediates are transient species that form during one step of a mechanism and then react further in subsequent steps. They do not appear in the overall balanced equation but are crucial for understanding how reactants are converted into products. Recognizing intermediates helps in deciphering the pathway and energy changes in a reaction.

Arrow-Pushing Formalism (Electron Flow)

Arrow-pushing formalism is a graphical tool used to depict the movement of electrons during chemical reactions. Curved arrows illustrate how electrons move from electron-rich areas to electron-poor sites, clarifying the stepwise progression and transformation of molecules in a reaction mechanism.

Transition States

Transition states are high-energy, unstable arrangements of atoms that occur at the peak of the energy barrier between reactants and products in each elementary step. Although they cannot be isolated, understanding the structure and energy of transition states is important for explaining the rate at which a reaction proceeds.

Kinetic Considerations

The rate at which individual steps occur can affect the overall reaction rate, with the slowest step often being the rate-determining step. Understanding kinetic aspects such as activation energy and the rate-determining step is essential for analyzing and predicting reaction behavior in a stepwise mechanism.

Transcript

00:01 This is the answer to chapter 16, problem number 45 from the smith organic chemistry textbook.

00:09 And we're asked to draw a stepwise mechanism for this reaction.

00:15 And so it is a hydrobromination of one of these two alkenes, and it's taking place under radical conditions.

00:27 And so we learned this reaction in the previous chapter, chapter 15.

00:32 And so hopefully you remember that when an alkenes is treated with hbr under radical conditions, the bromine is going to end up on the carbon with more hydrogens.

00:44 So this is going to be an anti -marcov -nakov type reaction.

00:50 And so the mechanism is going to look like this.

00:54 So first, we're going to have our radical initiator species.

01:00 So our peroxide species.

01:04 And to begin with, the oxygen -oxygen bond is going to cleave homilidically.

01:13 So that's where our radical comes from.

01:29 Okay, so we now have this or oxygen radical species.

01:35 And that is going to be what interacts with our first equivalent of hbr.

01:50 And so we end up having this happen.

02:05 So we have the alcohol here now.

02:08 And we also have a bromine radical.

02:20 And so it's going to be this bromine radical that now actually adds to our starting material.