Comments on: Partial Reduction of Alkynes With Na/NH3 To Obtain Trans Alkenes

By: James Ashenhurst

James Ashenhurst — Mon, 18 Mar 2024 17:35:03 +0000

In reply to aChemist.

For internal alkynes the reaction proceeds well with good yields.

The reaction works poorly for terminal alkynes, and even more poorly for acetylene. I mention the fact that the reaction works poorly for terminal alkynes in one of the quizzes.

Am I missing something? Because that doesn’t seem like much of a basis to call the article “largely incorrect”.

By: aChemist

aChemist — Mon, 11 Mar 2024 16:05:00 +0000

This article is largely incorrect unfortunately.

The reaction of 2 eq. Na in ammonia with 3 eq. acetylene only yields 1 eq. of ethene, and 2 eq. of sodium acetylide. The sodium that reduces the acetylene to ethene turns into sodium amide, which deprotonates acetylene to form the acetylide.

By: Asfan

Asfan — Sun, 01 Mar 2020 17:42:24 +0000

what happens in the reaction of alkynes with lithium aluminium hydride?
some sources say that LAH doesnt react with alkynes whereas some say partial hydrogenation takes place

By: Alkyne Reaction Patterns – The Carbocation Pathway — Master Organic Chemistry

Fri, 30 Oct 2015 19:45:45 +0000

[…] that are specific to alkynes (versus alkenes): deprotonation (and subsequent substitution), partial reduction to alkenes, and the formation of aldehydes and ketones through net “hydration”. With all the focus […]