Below are two reactions indicated in that will not likely tooccur? 1. NH 3 + CH

Question

Below are two reactions indicated in that will not likely tooccur? 1. NH3 + CH3OCH3 -->CH3NH2 + CH3OH 2. NH3 +CH3OH2+   -->CH3NH3+ + H2O
For (1), I believe that it will not occur since CH3- is a muchstronger base/Nu than NH3 but I have no idea why the second onedoes not occur.
Thanks. 1. NH3 + CH3OCH3 -->CH3NH2 + CH3OH 2. NH3 +CH3OH2+   -->CH3NH3+ + H2O
For (1), I believe that it will not occur since CH3- is a muchstronger base/Nu than NH3 but I have no idea why the second onedoes not occur.
Thanks.

Explanation / Answer

This is pka stuff and a CH3- is a rare/ nonexistent thing (inbeginning orgo, we'll only see deprotonated acetylene by strongNaNH2, NH3 (l), and again this is acetylene with two pi bonds, or anitrile functional group, or chloroform reactions, Simmons-Smith,and finally Grignards)--- otherwise you can assume Carbon'll fightto not get ripped off to become a nucleophile. You can see if your reactions will go to completion based onthe change (delta) of the pkas. So, if you write thereactant's acid and the product's acid: 10^(DELTA Product pkA -Reactant pkA) = "+" the reaction goes to completion, "-", thereaction favors the reactant formation. So with the pkAvalues (that we had to memorize, makes things pretty quick if youhave a tough reaction to judge its completion or not)  16 (CH3OH) - 35 (NH3) = -19, this is a professor's favorite way ofhearing that the reaction won't be completed (negative delta meansreactants favored, no product formed) . Another issue herewould be an FMO analysis that incorporates SN2 good NU/ good LGcombinations with favorable energies. So in 1, first you'dunfavorable make NH3 NH2- (which would likely just take back thatproton that O grabbed from it) rather than NH2- attacking aprotonated ether. This is not a good leaving group just causeits protonated. Evaluating the HOMO and LUMOs would helpalso. For number 2: Again, do the 10^delta pkA and you get the sameanswer: pka H20 is 16, pka NH3 is 35: 16 - 35 = -19,reactants favored, products not formed. I would stick toexplaining this the pka route tho.

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