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Topic: sn2 mechanism for ring opening  (Read 15541 times)

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Offline AWK

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Re: sn2 mechanism for ring opening
« Reply #15 on: February 28, 2008, 10:31:32 AM »
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Offline portugal

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Re: sn2 mechanism for ring opening
« Reply #16 on: February 28, 2008, 11:50:12 PM »
I have worked the product (3-bromo-2-butanol) and the mechanism out now for both the trans(2R, 3R) and Trans (2S,3S), however i have come across 2 products for each of them becuase of the equla probability that the C-O bond will be broken on either side and i need to know which one of each two is the major product. How am i supposed to know that???

Offline AWK

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Re: sn2 mechanism for ring opening
« Reply #17 on: February 29, 2008, 12:49:42 AM »
trans(2R, 3R) and Trans (2S,3S)
wrong using trans - trans suggest double bond

Quote
i need to know which one of each two is the major product. How am i supposed to know that???
It is normal in the case of more symmetric compounds that both products are formed in exactly the same amounts
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Offline azmanam

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Re: sn2 mechanism for ring opening
« Reply #18 on: February 29, 2008, 06:12:38 AM »
@ AWK: agreed.

cis/trans is generally reserved for geometry about a double bond, and sometimes for relative positions in a cyclic system.  syn/anti is also generally used for relative positions in a cyclic systems, but it can also be used for net creation of 2 new stereocenters. 

And you are correct, you form a racemic mixture of two products, and both will be formed in equal amounts.

I didn't check your r/s nomenclature, but assuming you prioritized each substituent correctly, then a job very well done.
Knowing why you got a question wrong is better than knowing that you got a question right.

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