Draw the structure that corresponds to each name and indicate which structures can exist as ster

Draw the structure that corresponds to each name and...

Key Concepts

IUPAC Nomenclature

This is the systematic method used to name organic compounds, ensuring that each compound has a unique, descriptive name. In the context of alkenes, it involves indicating the length of the carbon chain, the location of the double bond, and the placement of any substituents, which together allow for accurate identification and drawing of the molecule.

Structural Drawing

Structural drawing involves representing the connectivity of atoms in a molecule, including the arrangement of bonds and substituents. It is a critical skill for visualizing the actual molecular architecture from a systematic name and for identifying the positions where stereoisomerism might occur.

Alkene Stereoisomerism

Alkenes exhibit stereoisomerism due to the restricted rotation around the carbon-carbon double bond, leading to cis/trans or E/Z isomers. The spatial arrangement of substituents around the double bond is key to determining which molecules can exist as stereoisomers, making it an essential concept for analyzing molecules with alkene groups.

Transcript

00:03 Let us draw structures of molecules that could have stereo isomerism.

00:11 For the first one, three methyl, one, pentine.

00:14 Well, let's draw our pentine molecule to, oh, this will be, oopsies, this will be ch2.

00:27 Ch3 has a methyl, two, three, four, five carbons.

00:35 I'm going to redo this ethel group to make it look better.

00:40 Now the question is, can this molecule have stereo isomerism? can it be optically active? do you see a stereocenter? do you see something that could change about this molecule? is there lack of symmetry? all stereosomerism boils down to is, is there a lack of symmetry? if there is no symmetry, or if it's asymmetric, it can have stereoisomerism.

01:12 If it doesn't, then it can't.

01:14 And the best way to find this is, well, two hydrogens, that makes that one slightly, that makes that carbon slightly symmetrical, and that cannot happen.

01:28 Same for this carbon.

01:30 This carbon has a methyl group and two different substituents on either side.

01:36 On this side, it is completely different than on that side.

01:40 If i were to draw out all the hydrogens, you would have a hydrogen, say, on this carbon right here, you would have a hydrogen on top and a hydrogen on bottom.

01:49 This hydrogen and this hydrogen is exactly the same.

01:53 You cannot distinguish one from the other.

01:57 And therefore, well, that carbon itself is not optically active.

02:05 But this carbon is.

02:09 And so is this carbon.

02:11 And this carbon, however, is not because of those hydrogens.

02:15 Or at least we don't count it as a stereosomer if it does not have.

02:25 Those two hydrons.

02:26 Also, this carbons rules for stereoisomerism are a bit different.

02:32 So for this case, we will not call it a stereosomer either because of this double bond.

02:41 So in short, because of this one, there can be stereo isomerism.

02:49 Stereo isomers are possible.