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Winter Final 2012 Question 6B

Posted: Sat Mar 12, 2016 9:14 pm
by Michelle Yu 1L
for the 1-isopropyl -3- neopentylcyclohexane, how do you know it is neopentyl?

Re: Winter Final 2012 Question 6B

Posted: Sat Mar 12, 2016 10:12 pm
by jbcarton
You know it is neopentyl because it has 3 carbons branching off of from one carbon (giving it the neo) and there are a total of 5 carbons in the substituent (making it pentyl). In other problems it looks like a cross but it an also be drawn like this.

Re: Winter Final 2012 Question 6B

Posted: Sat Mar 12, 2016 11:04 pm
by Michelle Yu 1L
There was a similar problem where it was drawn like the this neopentyl but instead of neo it was named tert in final 2012 the first one of 6D. so I am confused between the two.

Re: Winter Final 2012 Question 6B

Posted: Sun Mar 13, 2016 11:08 pm
by VinayK 2B
A neo group is a group that has three methyl groups at the end and AT LEAST five carbons total, ie there is a secondary carbon connecting the branching side chain to the main chain. A tert-butyl group is a branching side chain that contains three methyls at the end and connects to the main chain via the tertiary carbon (once it is bonded to the chain, it is quaternary). The tert-butyl group is a sub-class of the neo branching.