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Topic: Why this product?  (Read 339 times)

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Offline JoeyBob

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Why this product?
« on: December 04, 2019, 05:26:08 PM »
So the double bond should be removed from the hydrogen catalyzed by nickel. But why would it go through a E1 reaction on a secondary halide if it's no longer allylic (since the double bond was removed from the hydrogen and nickel)?

Offline spirochete

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Re: Why this product?
« Reply #1 on: December 04, 2019, 08:49:52 PM »
The true mechanism is controversial, but secondary halides with ROH/H2O/RCO2H with heat give products consistent with carbocation formation. Most introductory texts draw the mechanism as E1/Sn1. I think only Paula Bruice calls it E2 in her textbook, but she also does not show many examples like this.

Offline hollytara

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Re: Why this product?
« Reply #2 on: December 04, 2019, 09:23:00 PM »
Hydrogenation turns alkene into alkane

The weak base, relatively high temperature leans toward E1.  E1 goes through a cation and therefore rearranges.  The most stable alkene it can form is the tetrasubstituted alkene (Zaitsev product).

You can get a good overview of all things organic in the book by Fredlos.

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