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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: nexisrocks on October 09, 2007, 08:45:14 PM

Title: BH3-THF Complex --> 1-Butanol Mechanism?
Post by: nexisrocks on October 09, 2007, 08:45:14 PM

I've been trying to determine the mechanism of the decomposition of the BH₃-THF complex into 1-butanol.  This was my stab at it:

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi2.photobucket.com%2Falbums%2Fy33%2Fshaylafitz%2FBH3-THFMechanism.jpg&hash=3d3924e5cd3fcadf29c499aa165fbcfe7d6a1de2)

I'm really not sure if this is the proper mechanism.  I am fairly certain that most of my steps are accurate, just possibly not in the right order.  I also put a bond between the BH₃ and THF, however I am also not sure if that is accurate.  I am not sure if the actually bond, or if they are just attracted to each other.

Any help would be greatly appreciated!

Title: Re: BH3-THF Complex --> 1-Butanol Mechanism?
Post by: Dan on October 10, 2007, 07:56:25 AM

Here's an interesting .pdf

http://www.basf.com/inorganics/pdfs/bulletins/BTHF.pdf

I would personally draw a concerted ring opening ring opening of THF. The decompostition of your BuOBH₂ that you have drawn would actually give you (neutral) BH if you follow the arrows, which strikes me as decidely dodgy. If, as shown in the pdf, once you have formed BuOBH₂ you then coordinate another THF and do the same as before you get (BuO)₂BH and do it again you then get (BuO)₃B.

Title: Re: BH3-THF Complex --> 1-Butanol Mechanism?
Post by: AWK on October 10, 2007, 08:25:08 AM

I doubt if this is a correct mechanism. BH3 easily reacts with a double bond. THF when heating can shightle decompose to 3-butenol, which can already react with BH3 giving H2B-CH2CH2CH2CH2OH, but oxidative decomposition of this compound leads to 1,4-butandiol