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Topic: problem in wolf kishner mechanism  (Read 1995 times)

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Offline ABA2015

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problem in wolf kishner mechanism
« on: October 08, 2014, 04:48:20 AM »
hi all
I can't understand why in organic mechanisms some times an atom such as N can have 4 valence and indicates as N+ but sometimes not, for example in wolf Kirchner mechanism as follow, but in manich reaction N can be positive with 4 valence
« Last Edit: October 08, 2014, 05:04:56 AM by ABA2015 »
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Offline ABA2015

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Re: problem in wolf kishner mechanism
« Reply #1 on: October 08, 2014, 05:03:07 AM »
sorry I could not attach the mechanism
 the known intermediate of wolf kishner is for example in acetone reaction with hydrazine (CH3)2-HC-N=NH why this one is not observed (CH3)2-HC=N+=NH
« Last Edit: October 08, 2014, 05:14:58 AM by ABA2015 »
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Offline mjc123

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Re: problem in wolf kishner mechanism
« Reply #2 on: October 08, 2014, 05:19:06 AM »
Because (CH3)2HC=N+=NH would have a 5-valent carbon. (and where is the negative charge?)
In H2C+-NMe2 the carbon has six electrons and a vacant p orbital, so N can donate its lone pair to form a pi bond, and the formal + charge shifts from C to N.
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