Devise a synthesis of each compound from the indicated starting material and any other required

Devise a synthesis of each compound from the indicated...

Key Concepts

Retrosynthetic Analysis

Retrosynthetic analysis is the strategy of deconstructing a target molecule into simpler precursor structures. This approach helps identify the key bonds to be formed and the sequence of reactions needed, making it easier to plan a synthetic route from available starting materials.

Functional Group Interconversion

Functional group interconversion involves transforming one functional group into another to achieve the necessary reactivity for subsequent steps. This is a fundamental concept in organic synthesis because it enables the modification of molecular functionalities, allowing for targeted reactivity and bond formation.

Reaction Mechanisms

Understanding reaction mechanisms is crucial in synthesis as it provides insight into how and why reactions occur. By knowing the step-by-step process at the molecular level, chemists can predict products, troubleshoot issues, and optimize conditions for each transformation within a synthesis.

Reagents and Reaction Conditions

Choosing the right reagents and reaction conditions is essential for driving each step of a synthesis efficiently and selectively. This encompasses not only the chemicals used for the transformation, but also the solvent, temperature, catalysts, and other factors that can influence the reaction outcome.

Selectivity and Regiochemistry

Selectivity and regiochemistry refer to the control over which specific position in a molecule reacts and the orientation of the substituents that are introduced. Mastery of these concepts is vital for synthesizing complex molecules, as it ensures the formation of the desired isomer with the correct structural arrangement.

Transcript

00:02 This is the answer to chapter 12, problem number 69, from the smith organic chemistry textbook.

00:10 And in this problem, we're asked to synthesize four molecules from four given starting materials.

00:19 And we're told we can use any other required reagents.

00:23 So to start with, in a, we need to get from this starting material here, this alken, to a carboxylic acid, but all that we really need to do is add that carboxylic acid.

00:41 We're not changing anything about the other carbons in the molecule or anything.

00:46 So a good way to start is going to be to install an alcohol, so a terminal, a primary alcohol here.

00:56 And we can do that.

01:04 Okay, there we go.

01:05 Sorry.

01:07 We can do that by using, for example, bh3 followed by hydrogen peroxide and hydroxide ion.

01:27 And so that's going to install the alcohol, the primary alcohol.

01:32 So if we were to use, for example, sulfuric acid and water, that would actually install the secondary alcohol instead.

01:41 But what we want here is this primary alcohol.

01:47 Okay.

01:48 And so there we go.

01:50 And then from here, it's just a simple chromium oxidation.

01:55 So we can use chromium trioxide, sulfuric acid, help if i wrote the right reagents.

02:10 So sulfuric acid and water.

02:12 And so that's going to, remember, that's going to oxidize a primary alcohol like this all the way up to the carboxylic acid.

02:22 So if we were used like pcc, that would stop at the aldehyde, but we want the carboxylic acid here.

02:31 And so chromium trioxide is a good reagent to use here.

02:37 C -o -o -h.

02:40 Okay.

02:40 And so there we go.

02:41 That's the product that we were asked to make for a.

02:43 So then for b, we're going to do something somewhat similar.

02:49 So we're starting from the alcohol here, the primary alcohol.

02:53 But in this case, we actually want the ketone.

02:57 So we want to go from this primary alcohol to a secondary alcohol on the next carbon over.

03:03 And then we'll oxidize that.

03:06 And rather than having a carboxylic acid, we'll have a ketone.

03:10 And so we can be, well, so let me draw the starting material.

03:14 So ch3, ch2, ch2, ch2, ch2, ch2oh.

03:27 Okay, so the first thing we need to do is dehydrate this primary alcohol.

03:33 And so concentrated sulfuric acid and water will dehydrate an alcohol.

03:40 So we now are at this alken.

03:43 And so we can again use so i guess the thing i forgot here is heat right so we need to heat in alcohol in concentrated acid and a little bit of water and that will get us our dehydration so if instead we use more dilute sulfuric acid here and so more water and no heat.

04:21 So now this is going to re -ad that alcohol, but it's going to be the secondary alcohol this time.

04:39 So there we go.

04:41 And then from here, we can just do an oxidation.

04:45 We could use chromium trioxide again, but i'm just going to use pcc.

04:51 Pcc is easy.

04:54 C .h3, ch2c.

04:57 C .h2c.

04:59 Ketone, ch3.

05:02 Okay, and so there's our final product for b.

05:07 So c on the next page here.

05:12 So in c, we need to go from cyclohexene to this molecule with a ketone and a triple bond in it.

05:27 And so a good way to start here.