June 04, 2020, 11:42:02 AM
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Topic: Can someone tell me why the following E1/E2 rxns change in stereochemistry?  (Read 906 times)

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Offline yourdeath01

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A) https://imgur.com/0Sm7bUF
1) Why is the CH3 going away in green arrow is just drawn as a normal bond with no stereochemistry in the products? 2) Why did we get two products 3) whats the major product?

B) https://imgur.com/To4cMhr
1) Same thing why did the CH3 bond coming in get drawn as a normal bond here?

C) https://imgur.com/R0FNE5v
1) Whats the major product here 2) Why get a triple bond, how did they do that? 3) Do I need to draw both or is the first alkene product okay?

D) https://imgur.com/tcwLned
1) In I. Why did the Br bond not go away and instead we get a CH3 group from i don't know where and the H goes up top? 2) In m. Also same thing, why Br bond is replaced with CH3 and why H is alternating in this E1?

All in all: I was under impression that only SN1/SN2 go through inversion/racemic products but the stereochemistry in the above E1/E2 is kind of weird and I am a lil bit confused on that.

Offline Babcock_Hall

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It is a forum rule (see red link above) that you must show your attempt before we can help you.  However, I will give you a small hint.  Think about the hybridization and geometry of the carbon with the methyl group.

Offline hollytara

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Think about the mechanism for each reaction - most of your examples are E1.  What is the intermediate in an E1 reaction?  A few are E2 - what are the requirements for an E2 reaction?

This will be covered in your textbook - or in the study guide by Fredlos.

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