Use full-headed or half-headed curved arrows to show the movement of electrons in each reaction.

Name: Problem 29, Chapter 6: Organic Chemistry
Uploaded: 2022-08-27T19:16:31-08:00
Duration: 4 min 2 s
Channel: Henry R
Description: Use full-headed or half-headed curved arrows to show the movement of electrons in each reaction.

Use full-headed or half-headed curved arrows to show the...

Key Concepts

Curved Arrow Notation

Curved arrow notation is used in mechanistic diagrams to depict the movement of electrons during a chemical reaction. The curved arrows show the flow of electrons from electron-rich areas (nucleophiles) to electron-deficient areas (electrophiles), thereby offering a visual representation of bond formation and bond breaking in step-by-step reaction mechanisms.

Electron Flow in Reaction Mechanisms

Electron flow is a fundamental concept in understanding how chemical reactions occur. It involves tracking the movement of electrons as bonds are broken and formed throughout the course of a reaction. This concept is central to predicting reaction outcomes and understanding the reactivity of various chemical species.

Full-headed Curved Arrows

Full-headed curved arrows, which have a complete arrowhead at the end, indicate the movement of a pair of electrons. They are typically used in reactions that involve the transfer or sharing of two electrons, such as the formation or breaking of covalent bonds in polar organic reactions.

Half-headed Curved Arrows

Half-headed curved arrows are used to represent the movement of a single electron, rather than a pair. This notation is especially important in radical reactions where electron transfer occurs one electron at a time, indicating the formation or involvement of radical intermediates.

Transcript

00:01 Okay, we've got a few reactions that we need to show the mechanism, or at least the steps using curved arrow formalism for...

00:13 I'm only going to draw the lone pairs that are absolutely necessary, but we're told that this is going to go to cyclohexanone with cl minus.

00:25 Okay, so i know that i need to form a new bond between oxygen and carbon, because i have a double bond.

00:32 Bond over here.

00:33 So i'm going to use this lone pair, drawing an arrow from that lone pair to the double bond to create a new bond.

00:39 I also know that i need to break this carbon chlorine bond.

00:42 So i'm going to draw an arrow from that bond to the chlorine to signify it leaving.

00:49 Right.

00:50 So that's where i'm going with this.

00:52 Okay.

00:54 Now we've got what looks to be a radical reaction.

00:58 And we've got br2.

01:03 One tricky thing is that.

01:05 That when you've got these radical reactions involving br2, it's always best to draw your br2 like this, because you need to have this bond to be able to break and form bonds with it.

01:17 And we know that this is going to basically brominate this and leave behind a bromine radical.

01:24 That's what they told us.

01:25 Okay, so we know we need to form a carbon bromine bond via radical mechanism.

01:31 So it's going to use a half -head arrow...

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