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![[Post New]](/templates/default/images/icon_minipost_new.gif) 17 Jan 2008 16:17:30 IST
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Which of the following reactions are not possible and why? Grignard reagent with 1.R'-C  C-H 2.R'-C C-R'' 3.R-CH=CH2 What is meant by acidic hydrogen?
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God has given you one face, and you
make yourself another.
~William Shakespeare
You were born an original. Don't die a copy.
~John Mason |
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17 Jan 2008 16:34:30 IST
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edited - yeah, 2 shud be right.... I was having a doubt bet 1 and 2... and john has cleared it. In 2, the carbon is not sufficiently positively charged due to the presence of bulky alkyl groups.
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Will nip in at times to solve problems :)
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17 Jan 2008 16:36:35 IST
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i think that the reaction in case 2 is not possible
here in case 2nd the necessary polarity for the reaction to occur is not available...
any hydrogen which is available in the form oh H+ is acidic hydrogen
in R-C(triple bond)C-H
the H is acidic hydrogen... because of the high polarity of the C-H bond this hydrogen is also available as H+ when reqd...
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~ANSHUMAN
I was born intellegent, education ruined me. |
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17 Jan 2008 16:42:20 IST
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It has been given that even reaction 3 is not possible......dont know the reason though..........is it something related to stearic hinderance?
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God has given you one face, and you
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~William Shakespeare
You were born an original. Don't die a copy.
~John Mason |
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17 Jan 2008 16:48:48 IST
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The very same reason applies to case 3 also...
Grignard reagent RMgX breaks as R- and +MgX
so the reaction takes place only when the reactant is sufficiently polar.
the polarity of double bond is much less than --C(triple bond)C-- or C=O and so the reaction will not take place...
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~ANSHUMAN
I was born intellegent, education ruined me. |
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17 Jan 2008 16:54:47 IST
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Then what about the reaction with a compound like R-CH3.....is it possible?
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~William Shakespeare
You were born an original. Don't die a copy.
~John Mason |
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such a compound cannot react with GR...
i dont think it is possible...
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~ANSHUMAN
I was born intellegent, education ruined me. |
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