Give IUPAC names for each of the following. FIGURES CANT...

Key Concepts

Functional Group Priority

Different functional groups have established priorities that determine both the suffix used in the compound’s name and the numbering of the carbon chain. Higher priority groups are assigned the lowest possible number and are generally considered the principal functional groups in the compound.

Numbering and Locants

Numbering the carbon chain of a compound is crucial in IUPAC nomenclature to assign locants, or numerical positions, to substituents and functional groups. This ensures that the substituents are correctly identified by their positions on the chain, aiding in the clear communication of the molecular structure.

IUPAC Nomenclature

This is a systematic method of naming organic compounds established by the International Union of Pure and Applied Chemistry (IUPAC). It provides a standardized naming convention that reflects the structure of the compound so that each name unambiguously describes the corresponding molecular structure.

Selection of the Longest Carbon Chain

When naming an organic compound, the longest continuous carbon chain is identified as the parent hydrocarbon. The choice of this chain influences the base name of the compound and helps dictate the numbering of carbon atoms in the molecule.

Substituent Naming and Prefixes

Substituents attached to the parent chain are named using appropriate prefixes. Their names, along with the locants determined by the numbering system, are incorporated into the final compound name. Multiplicative prefixes (e.g., di-, tri-) are used when multiple identical substituents are present.

Transcript

00:04 Let's practice some nomenclature.

00:07 Well, for the first molecule, well, we have a cyclohegene.

00:11 So we know that we have a cyclohegene.

00:15 And we have one methyl and one bromo, which one would be the first carbon? well, the b becomes before m and also a halo alkan or a halogen has more priority than just an alkyl group.

00:32 So by default, the bromine would be one.

00:34 So we have one bromo, one bromide, two methyl cyclohexane.

00:49 So far so good.

00:50 Now we need to worry about stereochemistry because it is assigned.

00:56 Well, if we take carbon one and assign priority, bromine gets top priority.

01:03 Carbon two would get second priority because there are two groups branching off of it as opposed to just one on the other side, and three.

01:14 Going clockwise, we know that's r.

01:16 So we know that we have one r, one r.

01:25 What about two? well, we can do the same thing.

01:29 For carbon number two, the bromine side, or this carbon right here, with the bromine would be first priority.

01:39 Second priority would be into the ring because it continues, whereas the methyl group truncates.

01:46 And finally, the methyl group would be three.

01:49 It goes counterclockwise.

01:51 We know that to be s.

01:53 1r2s, 1 bromo, 2 methyl cyclohegene.

01:57 And that is the name of this molecule.

02:02 Let's try this one.

02:05 Now this one's highly similar to the previous example, except now we are in a chair conformer for our cyclohegene.

02:14 So, well, we know that we can say, this is carbon one, two, three, or alternative one, two, three, four, five.

02:26 Yes.

02:27 So we can either say it's one five or it's one three.

02:31 Obviously we want to go with one three because that involves lower numbers.

02:37 We always want to keep things simple, right? and this is still going to be a cyclohegane.

02:42 Chair conformer doesn't really have any nomenclature to itself, so we can just call it cyclohegane.

02:47 So we know it'll be one bromoprome, three methyl cyclohexane.

03:01 However, we're not done.

03:04 There is stereochemistry given, and it's not very clear, but it is present.

03:09 And the idea is, in chair conformers, if something is pointed up, we can consider it as a wedge as if it was drawn as a conventional cyclohegane.

03:19 If it was a dash, or if it's pointed down or kind of down and out, any form of up and up and out, like it can be axial or equatorial.

03:34 The axial equatorial part doesn't matter.

03:37 What matters is whether it's pointed up or pointed down.

03:41 So notice how the bromine is pointing down and the methyl is also pointed down...

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