[cabaal]

I've read my text (and several other supplementary sources) and I understand what an asymmetrical carbon is: a carbon with four attached, DIFFERENT groups.



I was asked to find the asymmetrical carbons in this compound. They are highlighted in green. I don't understand why some (most of them) are considered asymmetrical.

Take the leftmost green carbon. It's attached to a CH2, an -OH, an H, and a CH2. There are two CH2 groups. Why is it then an asymmetrical carbon?

The same with the second (left to right) hexane. Why is the bottom most carbon green? It's connected to a CH, an H, a CH2, and a CH. There are two CHs.

[sjb]

Taking the leftmost carbon, whilst it's true at distance one atom it's attached to an oxygen, a hydrogen and two methylenes, what happens when you go beyond the methylene - are the branches still the same?

[cabaal]

Oh, so I keep going along the chain until there's a point of difference?

[bromidewind]

Oh, so I keep going along the chain until there's a point of difference?

Yup. Recall naming rules for R-S stereoisomers. You regard each attached molecule by its weight and assign it a priority. In case of a tie, go to the next atom until one chain winds up being heavier than the other. You only stop considering atoms when there's no more in the chain, i.e. H's or terminal methyl groups.

[sjb]

Oh, so I keep going along the chain until there's a point of difference?

Yup. Recall naming rules for R-S stereoisomers. You regard each attached molecule by its weight and assign it a priority. In case of a tie, go to the next atom until one chain winds up being heavier than the other. You only stop considering atoms when there's no more in the chain, i.e. H's or terminal methyl groups.

To be pedantic, you don't need to stop at methyls, as you may get things like deuteration affecting matters, so 1-deuterio-2-bromopropane is also chiral