What will be the product of.........?.........

the answer is......

can anybody explain the mechanism plzzzzzzz.............

NBS IS USED TO RELEASE BROMINE FREE RADICAL.........

AND THEN THE ADDITION OF FREE RADICAL TO ALKANES GIVES THE DESIRED BRODUCT.

1.BROMINE FREE CRADICAL IS RELEASED

2. THEN THE FREE RADICAL(DOUBLE BOND KE UPPAR ADJACENT CARBON PAR) IS GENERATED.

3.THEN FOR THE STABLE INTERMEDIATE,DOUBLE BOND SHIFTS UPPER AND METHYL GRP KE SAATH KE NICHE WALA RADICAL BAN JATA HAI.....

4 THEN THE BROMINE FREE RADICAL REACTS AND U GET THE ANSWER.........

HOPE U GOT IT.............IF NOT .....THEN TELL ME HOW TO MAKE PICT........I WOULD EXPLAIN BY THAT..... 

NBS does substitution raeaction, because of its low concentration, it diverts the path of reaction from Addition to substitution..

ANSWER:

The carbon with 2 methyl grps is '1'

going in clockwise direction i've numbered the carbons as '2' and  '3' and '4' respectively.

Actually what happens is that, as the Br radical is released, it attacks on carbon '4' because its an allylic carbon, and the intermediate radical formed will be resonance stabilized.

Now if you see which Carbon will be stable with a free radical on it, the answer will be Carbon no '2'

it will be slightly more stable than free radical on '4'



because of more number of hyperconjugation and more inductive effect.

Therefore, atom no. '2' will be the free radical and now it will attack on the Br molecule and the desired product will be formed, hope its clear now :)

@svj29......

DON T BE PROUDY!......







HEY MAN DONT U HAVE THE EYES....................UR ANSWER IS CORRECT BUT I THINK I HAVE ALREADY GIVEN THE RIGHT STEPS (AGREED BY TARIN) ........READ IT PROPERLY AND COMPLETELY  AND THEN LEARN HOW TO COMMENT........

 ADDITION OF BROMINE FREE RADICAL TO ALKANES.............IS ENOUGH TO CLARIFY THE SUBSTITUTION PROCESS.....BECAUSE ALKANES DONT UNDERGO ADDITION REACTIONS.....(THIS IS GENERALLY THE FOURTH STEP IN MY FIRST REPLY.....)

@JASBIR......I AM NOT ABLE TO DRAW IMAGES....,BUT THE STEPS ARE ENOUGH TO MAKE U CLEAR IF U KNOW THE GOC.........ELSE TELL ME HOW TO MAKE IMAGES.

NBS is useful in making BROMINATION at ALLYLIC position.