Eight alcohols have the formula C5 H12 O. Draw them. Which are chiral?

Name: Problem 34, Chapter 5: Organic Chemistry
Uploaded: 2020-06-24T07:10:17-08:00
Duration: 5 min 4 s
Channel: Travis Maslanik
Description: Eight alcohols have the formula C5 H12 O. Draw them. Which are chiral?

Eight alcohols have the formula C5 H12 O. Draw them. Which...

Key Concepts

IUPAC Nomenclature

IUPAC nomenclature is the systematic method used to name organic compounds. It involves identifying the longest carbon chain, determining the position of functional groups like the hydroxyl group, and assigning appropriate prefixes or suffixes. This ensures clarity and consistency in naming the structural isomers and helps in differentiating between the various C5H12O alcohols.

Chirality

Chirality in organic molecules refers to the presence of a chiral center—a carbon atom that is bonded to four different substituents—resulting in non-superimposable mirror images (enantiomers). Detecting chirality involves identifying these centers, and it is significant in understanding whether a molecule will exhibit optical activity, which is a critical aspect of stereochemistry.

Alcohol Functional Group

The alcohol functional group is defined by the hydroxyl (-OH) group bonded to a carbon atom. This group is responsible for the characteristic properties of alcohols, such as hydrogen bonding and polarity, affecting both their chemical reactivity and physical properties. Its placement in the molecule (primary, secondary, or tertiary) is key to differentiating between isomers.

Structural Isomerism

Structural isomerism is the concept where compounds sharing the same molecular formula have different connectivity or arrangements of atoms. In the context of C5H12O alcohols, this means that while the molecular formula remains constant, the way in which the carbon skeleton ( backbone) is arranged and the position of the hydroxyl (-OH) group can vary, leading to multiple distinct compounds.

Transcript

00:01 So i have the molecular formula c5h12o, and i'm also told that i have eight different alcohols that correspond with this molecular formula.

00:09 And so what i want to go ahead and do is just draw each one of them and label which of them, which of those are going to be chiro.

00:16 So what i like to do is just go ahead and start with my parent chain, being five carbons.

00:22 And so what's that going to look like? well, it's going to look like this.

00:27 And then, of course, i'm going to have my alcohol attached to that.

00:31 And that does meet my molecular formula.

00:34 And so that would be one alcohol.

00:39 And then what i like to do, and now what i like to do is just go ahead and move that alcohol group around.

00:44 So where here it's going to be a one petanol.

00:46 I'll go ahead and make it a two petanol.

00:48 And so what is that going to look like? and so i have two petanol now.

00:54 And now i can just move it around to the three position.

00:57 And now i have three petanol, right? so that looks like this.

01:03 Of course, i wouldn't have four or five petanol because that would just be the same thing as one and two.

01:07 And so now what i can do is, and now i can make it such that my parent chain only has four now, and i could start moving the methyl group around.

01:20 So what i can draw is, for example, i can still have a primary alcohol, so i can have the following, right? but now i can move my methyl group around, and i wouldn't put it in the one position because that's going to be the same thing as our two pentanyl.

01:37 And so what if i try putting our method group in the two position, what is that going to look like? well, it looks like something like that.

01:43 And now i can move it to the three position.

01:46 And so, you know, what is that going to look like, right? so it'll look like this, where my method group is now in the three position.

01:56 And now what i can do is i can make it a secondary alcohol with the same parent chain being a butane.

02:05 So i'll keep the same parent chain here.

02:10 So i have a butane, and now i can be a secondary alcohol, right? and now i can add my methyl group on the 2 and 3 position.

02:17 So i'll go ahead and put it on the 2 position with the alcohol.

02:22 And so i have the 2 -methyl -2 butanol, and now i could put it on the 3 position.

02:27 And so it's going to look like this.

02:30 Right, so i saw my secondary alcohol there, and now i have that in the 3 position.

02:36 Okay.

02:37 So that gives me 7, and now that helps me with all my butane and my pentane parent chains.

02:44 And what if i go to my propane parent chain? what is that going to look like? so i'm going to have my propane parent chain...

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