Draw a stepwise mechanism for the following reaction, which was used in the synthesis of the eze

Draw a stepwise mechanism for the following reaction, which...

Key Concepts

Stepwise Reaction Mechanism

This concept refers to the idea that a complex organic reaction occurs in a series of individual steps, each with its own transition state and, often, intermediate species. Understanding the stepwise nature of a mechanism helps elucidate how bonds are broken and formed sequentially, laying a clear pathway from reactants to products.

Reaction Intermediates and Transition States

In multistep reactions, intermediates are transient species that exist between the initial and final products, and they typically occupy local energy minima on the reaction profile. Transition states, on the other hand, are high-energy configurations that occur during the conversion from one intermediate to another. Analyzing these helps in understanding the kinetics and thermodynamics of the reaction process.

Nucleophilic and Electrophilic Interactions

Many organic reactions are driven by interactions between nucleophiles—species that donate electron pairs—and electrophiles—species that accept electron pairs. Recognizing which atoms or functional groups act as nucleophiles and electrophiles in a reaction mechanism is key to predicting how the reaction proceeds.

Curved Arrow Notation

Curved arrow notation is a symbolic way to depict the movement of electrons during each step of an organic reaction. It provides insight into how electrons shift from one part of the molecule to another, helping to visualize the mechanism and rationalize the formation and breaking of chemical bonds.

Transcript

00:02 This is the answer to chapter 24, problem number 69, from the smith organic chemistry textbook.

00:10 This problem asks us to draw a stepwise mechanism for this reaction, which was used in the synthesis of a drug for high cholesterol.

00:21 Okay, and so this is just going to be a pretty straightforward enolate formation, and then the enolate is going to act as a nucleophile.

00:36 So the first thing that's going to happen is going to be deprotonation of this alpha proton by lda.

01:01 Okay, so once this deprotonation occurs, we have the enolate.

01:07 And now that enolate, oh, and i should mention this, right? so i am abbreviating this large molecule with two arrow groups in it the way that i've drawn at the top of the screen here.

01:21 So that is where this molecule comes in.

01:27 So ar and ar prime to denote the two arrow groups.

01:32 It's a pretty common abbreviation.

01:36 And so the attack is going to happen here.

01:44 These electrons will go here to the nitrogen.

01:49 And so after that step, we are here.

02:02 So i'm also going to draw this in the confirmation that makes it sort of easy to see how we get to our final product.

02:10 It's always a good idea to do as well.

02:29 Okay.

02:31 The nitrogen has two lone pairs, and so a negative charge.

02:37 And so it is now going to be able to attack this carbonyl right here...