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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: mrstrh on September 28, 2004, 04:21:32 PM

Title: Preparing 2,7-dimethyoctane and (CH3)3CCH(CH3)2
Post by: mrstrh on September 28, 2004, 04:21:32 PM: how do you prepare 2,7-dimethyoctane form 1-bromo-3-methylbutane.

How do you also Prepare (CH3)3CCH(CH3)2 from t-butyl bromide.

how do you do these and how do you come to a conclusion? i was thinking you could use the grignard reagent but i really dont know how to set it up yet im really new to organic right now.

Edit: Edited subject for clarity.--Mitch
Title: Re:organic help needed bad
Post by: movies on September 28, 2004, 06:56:13 PM: Have you heard of a Kumada coupling? That'll do it, I think. You might also look up the Corey-House and the Wurtz reactions. There are other ways, but they would take a couple of steps. If none of the name reactions I mentioned mean anything to you, then you are probably going to have to do it in a more stepwise fashion.

The second one can be done with a Grignard. What would you want to quench the t-butyl Grignard reagent with?
Title: Re:organic help needed bad
Post by: Mitch on September 28, 2004, 07:20:49 PM: The Wurtz reaction would be the ultra-simplest for the 1st reaction.
Title: Re:organic help needed bad
Post by: mrstrh on September 28, 2004, 09:58:48 PM: how is the wurst reaction done for these?

how do you prepare 2,7-dimethyoctane form 1-bromo-3-methylbutane.

How do you also Prepare (CH3)3CCH(CH3)2 from t-butyl bromide.
Title: Re:organic help needed bad
Post by: movies on September 28, 2004, 10:24:56 PM: The Wurtz reaction: http://www.chempensoftware.com/reactions/RXN421.htm

I don't think you could use the Wurtz for the second one though.
Title: Re:organic help needed bad
Post by: AWK on September 29, 2004, 02:52:30 AM: Wurtz coupling:
http://www.organic-chemistry.org/frames.htm?http://www.organic-chemistry.org/namedreactions/wurtz-reaction.shtm
the second problem can be solved by modified Wurtz reaction with Grignard reagent formed from isopropyl bromide (+ t-butyl bromide) - Wurtz-Grignard (or Houben) reaction
Title: Re:organic help needed bad
Post by: movies on September 29, 2004, 01:09:26 PM: So you can do a "hetero-Wurtz" reaction, that's very interesting. The activity of the Grignard is such that it reacts faster than the dimerization of the starting alkyl halide via normal Wurtz reaction?

Where have you seen it called the Houben reaction? I can only find the Houben-Hoesch, which is very different.
Title: Re:organic help needed bad
Post by: Mitch on October 02, 2004, 07:55:11 PM: Added the Wurtz reaction to our name reactions page, I'm still working on correcting some things AWK pointed out on other mechanisms.