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Topic: Hydrohalogenation (Addtion to alkene)  (Read 4047 times)

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noartno

  • Guest
Hydrohalogenation (Addtion to alkene)
« on: November 15, 2005, 04:42:50 AM »
hi, my question is
the reaction of 3-methylcyclopentene with HBr yields?

i'm remember from the lecture that when both double-bond carbon atoms have the same degree of substitution, a mixture of addtion products result and markovnikov's rule will not apply.
is this apply to the above question??
« Last Edit: November 15, 2005, 04:46:09 AM by noartno »

Arsenic

  • Guest
Re:Hydrohalogenation (Addtion to alkene)
« Reply #1 on: November 15, 2005, 06:50:28 AM »
mech.I :Since a carbocation is formed during the addition process, it is subject to the rearrangment  problems inherent to such species. this process is under thermodynamic control and tends to give the more stable ion and the more stable product.

mech.II :reaction proceeds by a radical intermediate,the radical is formed when Br.(radical) is attacked by the pi-bond of the alkene.The bromine atom rather than hydrogen(mech.I) adds first to produce the more stable radical ,in this case the two radicals have the same stability hence equal amounts of a and b should be formed.
« Last Edit: November 15, 2005, 06:53:49 AM by Arsenic »

noartno

  • Guest
Re:Hydrohalogenation (Addtion to alkene)
« Reply #2 on: November 15, 2005, 08:42:45 AM »
thanks  ;D

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