Deprotonation of alkynes with base to give acetylide ions
Description: Treatment of an acetylene with a strong base such as NaNH2 results in acetylide ions
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Org. Synth. 1962, 42, 97
DOI Link: 10.15227/orgsyn.042.0097
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8 thoughts on “Deprotonation of alkynes with base to give acetylide ions”
Also in this: “Note that NH3 is the byproduct here. NaNH2 or KNH3…” it should be KNH2.
In the second example, the cation in the product should be K+.
Why wouldnt a base such as tBuCl work in this case to deprotonate a terminal alkyne?
tBuCl is not a base; do you mean t-BuO(-) ? Given the large pKa difference between tBuoH (17) and alkyne (25) the equilibrium will lie on the side of t-BuO- , so it’s more useful to use a strong base like NaNH2 (pka of conjugate acid 38) to deprotonate the alkyne irreversibly.
I’ve got an exam question problem: So I’ve added n-BuLi to an alkyne, from this a suspect I product lithium acetylide, however the question asks for ANOTHER reagent in the reaction, could it be LiH4-, to get rid of the lithium or is there something im missing?