Chemical Forums

Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: nilgnay2 on July 24, 2006, 03:23:45 AM

Title: cyclobutyl bromide (Bromocyclobutane)
Post by: nilgnay2 on July 24, 2006, 03:23:45 AM
Hello everyone:
   I want you can give me a help for the synthesis of cyclobutyl bromide.
The below is needed:
   The first reagent must be cyclopropylcarbinol.
Could you suggest me a road to synthesize this compound? I'll appreciate for your help.Thank you!
Title: Re: cyclobutyl bromide (Bromocyclobutane)
Post by: GSR on July 24, 2006, 09:42:26 AM
hi,

here is some procedure


                          hot alkaline KMno4/or  CrO3 in H2SO4     HgO, Br2,heat
cyclopropylcarbinol   ----------->  cyclobutanecarboxylic aid       ------------>        cyclobutyl bromide
                                                                                  ccl4, dark

you can get the procedure for the conversion of acid to halide from Organic Syntheses, Coll. Vol. 6, p.179 (1988); Vol. 51, p.106 (1971)
which is available free by searching from http://www.orgsyn.org/( MERCURY(II) OXIDE-MODIFIED HUNSDIECKER REACTION: 1-BROMO-3-CHLOROCYCLOBUTANE.

hope this will help you.

cheers

GSR
Title: Re: cyclobutyl bromide (Bromocyclobutane)
Post by: HP on July 24, 2006, 12:34:29 PM
Well, HgO is pretty nasty reagent to work up with and also  Hunsdiecker and Borodin many years before has done this reaction with Ag-salt carboxylic acid and Br2...
Title: Re: cyclobutyl bromide (Bromocyclobutane)
Post by: movies on July 24, 2006, 08:54:18 PM
                          hot alkaline KMno4/or  CrO3 in H2SO4     HgO, Br2,heat
cyclopropylcarbinol   ----------->  cyclobutanecarboxylic aid       ------------>        cyclobutyl bromide
                                                                                  ccl4, dark

Are you sure that's correct?  Seems to me you added a carbon in the first step.

I think that you can convert cyclopropyl carbinol to cyclobutyl bromide by just treating the alcohol with PBr3 or POBr3.  First making the cyclopropylcarbinyl cation which can rearrange to cyclobutyl cation which could be trapped with Br-.
Title: Re: cyclobutyl bromide (Bromocyclobutane)
Post by: wereworm73 on July 25, 2006, 03:50:50 PM
You don't need to bother with the permaganate.  Just heat the cyclopropylcarbinol in 2M HCl at 100oC and then treat the resulting cyclobutanol with PBr3 to convert it to a bromide. 

Movies' idea could be a nice shortcut, though.  You might want to test a little bit of cyclopropylcarbinol with PBr3 and see if you get a good yield of bromocyclobutane.   
Title: Re: cyclobutyl bromide (Bromocyclobutane)
Post by: nilgnay2 on July 27, 2006, 09:54:58 AM
       .
I think that you can convert cyclopropyl carbinol to cyclobutyl bromide by just treating the alcohol with PBr3 or POBr3.  First making the cyclopropylcarbinyl cation which can rearrange to cyclobutyl cation which could be trapped with Br-.
Oh,thank you for your advice, I think it is a good road to convert cyclopropylcarbinyl to cyclobutylbromide.
And, your mechanism is correct.
I'll have a try by the method that your adviced, and the method adviced by wereworm73
thank you !