Why ammonia is a best leaving group comparable water molecule?
Answers
Explanation:
I've learned in several textbooks, that in the nucleophilic acyl substitution H2O is a better leaving group than NH3. This can be explained by the "thumb rule" of the pKa. NH3 is more basic (pKb(NH3)=4.3) than H2O (pKb(H2O)=15.4) and therefore a worser leaving group.
But what is the reason for the fact, that the following common reaction happen (and the worser leaving group has left the molecule)?
My idea: Is it more a kind of "equilibrium discussion"? The reaction can happen but the equilibrium lies not really on the "product side"? Compared to another nucleophilic acyl substitution (e.g. water with a acyl chloride) this equilibrium lies far more on the educt side. But nevertheless, this reaction happens and can be exploited for example in the Strecker Synthesis through several methods (Le Chatelier, etc.)?
Additional idea: The excess of water can push the equillibrium to the product.
Answer:
Essentially, convert the ammonium ion function to a functional group which will allow the use of a strong base, like hydroxide anion.
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