Destroyer # 23 Ochem

[luv8724]

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Monochlorination of 2-methylbutane... how many products are expected if stereoisomers were counted...


Chad said there are 5 of them.. but destroyer said 6.. what is right?

I would say 5 but...

 

[UCB05]

I count 6:

1/2: chlorination of C1 or methyl group makes C2 a chiral center
3: chlorination of C2
4/5: chlorination of C3 makes a chiral center
6: chlorination of C4

which one does chad not count?

 

[gigawatt]

I count 6:

1/2: chlorination of C1 or methyl group makes C2 a chiral center
3: chlorination of C2
4/5: chlorination of C3 makes a chiral center
6: chlorination of C4

which one does chad not count?

UCB's right. When I first counted I missed counting C3 twice because it is prochiral, but 6 is right. Gotta be careful.

 

[CANgnome]

Chad is incorrect in this case. I went over his notes today and saw this too.

it is 6.

 

[PaulieGualtieri]

Chad is incorrect in this case. I went over his notes today and saw this too.

it is 6.

2 days, good luck!

 

[flyingforever]

I count 6:

1/2: chlorination of C1 or methyl group makes C2 a chiral center
3: chlorination of C2
4/5: chlorination of C3 makes a chiral center
6: chlorination of C4

which one does chad not count?

Chad is correct. It makes only 5.
C2 position is not a chiral center. Look carefully. You will find two methyl groups, chlorine group, and propyl group.

 

[UCB05]

Chad is correct. It makes only 5.
C2 position is not a chiral center. Look carefully. You will find two methyl groups, chlorine group, and propyl group.

I didn't say it was. It's just another product. Which means it still counts. The question isn't asking for stereoisomers. Just different products.

 

[CANgnome]

2 days, good luck!

thanks 🙂

 

[flyingforever]

I didn't say it was. It's just another product. Which means it still counts. The question isn't asking for stereoisomers. Just different products.

Please explain how are you getting one extra product even though C2 is not chiral. Where is the enantiomer coming from?

 

[CANgnome]

the chlorine has the possibility of adding to either methyl groups, so in effect you can get a pseudo-R and pseudo-S (I do not know how to term this)

 

[UCB05]

Please explain how are you getting one extra product even though C2 is not chiral. Where is the enantiomer coming from?

I didn't say you get two products from chlorination of C2. You get one productbecause C2 is not chiral. However, when you chlorinate one of the methyl groups (C1 or the methyl substituent), THAT reaction makes C2 chiral, because now you have hydrogen, ethyl, methyl, and chloromethyl groups attached to it, which gives two additional products distinct from the C2 chlorination product. That's 2+1. Chlorination of C3 makes another 2 chiral products, and chlorination of C4 makes one more product. 6 total.

 

[flyingforever]

Gottcha, tricky question 🙄