Kaplan Midterm Orgo #93

[Dentite99]

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I know this may seem like a simple question, but i feel like their answer is incorrect:

The reaction of 1-butene with hydrogen bromide in the presence of UV light results in the formation of:

Their answer: 1-bromobutane

My answer: But i thought Br would add to the secondary Carbon to be 2-bromobutane, since there's no H202.

weird.

 

[dentista123]

UV light does the same thing as H2O2= Anti-Mark

 

[dentista123]

When you see peroxide, think ANTI- MARK, possible polymerization, and epoxidation.

Overall, think something weird can happen.

 

[Dentite99]

Great, thanks for your help.

 

[GiTsticker]

UV light does the same thing as H2O2= Anti-Mark

This is wrong. Br radicals are selective and react slower than Cl radicals. Cl radicals are less predictable because they will react to form mixed products of primary and secondary halides whereas the Br radicals react slower and will prefer the secondary carbon.

 

[dentista123]

This is wrong. Br radicals are selective and react slower than Cl radicals. Cl radicals are less predictable because they will react to form mixed products of primary and secondary halides whereas the Br radicals react slower and will prefer the secondary carbon.

For this particular question at hand, they react in the same fashion. That is..anti-mark. I was not getting into technicalities nor mechanisms.

Like the difference between HCl HV and HBr HV...In the question above, they both add anti-mark. To my knowledge, that is correct.

 

[GiTsticker]

You're right, sorry haha...I was thinking Br2 + uv on an alkane. -totally different.