[maakii]

Hi everyone!

In the wikipedia article on the Cahn Ingold Prelog rule, http://en.wikipedia.org/wiki/Cahn_Ingold_Prelog_priority_rulesI came across this example:

-CH2CH2OH outranks -CH(CH3)2

Now, is this an error? Because the first carbon in red is only a primary carbon, while the second carbon in blue is secondary, so by right the order should be the other way around? 

[sjb]

Whether a carbon is primary or secondary has (little or) nothing to do with priority by CIP.

-CH₂CH₂OH outranks -CH(CH₃)₂ because if you move along the chain with the highest priority in the first chain you use C-C-O, in the second C-C-H, hence the alcohol is higher than the isopropyl group.

(At least, that's how I understand it)

S

[AWK]

Hi everyone!

In the wikipedia article on the Cahn Ingold Prelog rule, http://en.wikipedia.org/wiki/Cahn_Ingold_Prelog_priority_rulesI came across this example:

-CH2CH2OH outranks -CH(CH3)2

Now, is this an error? Because the first carbon in red is only a primary carbon, while the second carbon in blue is secondary, so by right the order should be the other way around? 

You are right. -CH(CH3)2 has higher priority than -CH2CH2OH

[kiwi]

yep as AWK said, you have it right. Not sure where the wikipedia error comes from, but it looks like someone has misunderstood the example in March (pg 139). I've changed the wikipedia example to something more relevant.

[sjb]

OK, sits corrected, sorry

S