0
$\begingroup$

I found a question to determine the number of possible chiral products of monochlorination of 2-chloropentane.So, first the products are (with possible number of enantiomers in the parentheses:

2,2-dichloropentane(no chiral product),

1,2-dichloropentane(4 or 2, I am not sure is there a plane of symmetry here)

2,3-dichloropentane(2 or 4)

2,4-dichloropentane(obviously none for a plane of symmetry)

2,5-dichloropentane(2,4?)

But my surprisingly the answer says it's only 5. That's even lower than my lower estimate. I am not sure how there are 5 enantiomers.

$\endgroup$
  • $\begingroup$ Chlorination at 2°carbon is more probable to happen here if we consider the thermodynamics of the reaction but still I am confused about having just 5 products. $\endgroup$ – Suraj S May 10 '17 at 17:19
  • $\begingroup$ I am not. Narendra Kumar answer is right. $\endgroup$ – Mockingbird May 11 '17 at 12:34
3
$\begingroup$

2-chloropentane is optically active compound hence in some cases we will get only diastereomers. For example 1,2-dichloropentane is single product because it is formed by attack at carbon no. 1 hence no change in chirality of carbon no. 2. So product formed by attack at carbon 1 (one chiral product) carbon3 (two chiral product i.e. diastereomers) carbon 4 (one chiral product, i.e. one chiral and one meso) carbon5 (one chiral product)

$\endgroup$
-2
$\begingroup$

The answer is 5. See- 1) 1,2 dichloropentane --- 1 chiral 2) 2,3 dichloropentane --- 2 chiral 3) 2,4 dichloropentane --- not chiral as there is plane of symmetry 4) 2,5 dichloropentane -- 2 chiral

Therefore 2+1+2 =5 Chiral Products

$\endgroup$
  • $\begingroup$ why 2 chiral products when there are 2 stereocenters in 2,3-dichloropentane? $\endgroup$ – Mockingbird May 10 '17 at 11:28
  • $\begingroup$ It would be better if you explain it better. $\endgroup$ – Mockingbird May 10 '17 at 11:31
  • 6
    $\begingroup$ Please don't use all caps. $\endgroup$ – orthocresol May 10 '17 at 12:37
  • $\begingroup$ @pritt Balagopal Are u sure this answer is right? and why 2 chiral products when there are 2 stereocenters in 2,3-dichloropentane? $\endgroup$ – Mockingbird May 11 '17 at 11:16
  • $\begingroup$ I think there won't be 2 enantiomers for 2,5-dichloropropane. only 1. and 2,4-dichloropropane would have 1 enantiomer $\endgroup$ – Mockingbird May 11 '17 at 12:33

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.