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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: sveioen on October 13, 2009, 12:42:40 PM

Title: How to find chiral atoms in ring structures
Post by: sveioen on October 13, 2009, 12:42:40 PM

Hey all,

how do you find chiral centers in ring structures? Say, on glucose in the open aldehyde form (straight chain) you just evaluate each C-atom to see if they're connected to 4 different groups. But when you have a ring structure, the structure is "biting it's own tail" (sort of..), so how do you check if a C-atom is connected to 4 different groups?

Title: Re: How to find chiral atoms in ring structures
Post by: Arctic-Nation on October 13, 2009, 02:03:12 PM

You do it in exactly the same way as with linear molecules, really. The easiest is to evaluate the two neighbouring carbon atoms against each other, and if they're the same, evaluate their respective neighbours against each other, and so down each side of the ring till you find a difference or hit 180°. With simple sugars this only takes two iterations. Just be careful that you evaluate the right atoms against each other.