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Thursday, August 11, 2005

Zinc reduction of alkynes



A traditional method for the reduction of alkynes to trans-alkenes is to dissolve metal reduction using sodium or lithium in ammonia. However, we can also use Zinc as a metal to reduce alkynes.

In this specific case, by changing the proton source in the reaction, the dissolving Zinc metal reduction of ethyl phenylpropiolate to the corresponding cinnamate ester can be stereochemically controlled.

The product of the reaction will be a mixture of cis and trans ester. By this reaction, we can see the efficiency of Zinc in the reduction of alkynes.

For more reference, please click on:
http://www.citeulike.org/user/hongan1985/article/279061

2 Comments:

  • This is a very interesting reaction of how to control stereochemistry of reduction by using various acids. However, you must produce at least one SPECIFIC reaction. Pick an acid and put the ratios of the products. Also remember to explain all abbreviations (e.g. THF). You can certainly then mention how the ratios change with different acids.

    By Blogger Jean-Claude Bradley, at 6:47 AM  

  • Full marks. It would have been nice to talk about how the use of another specific acid can reverse the cis/trans ratio.

    By Blogger Jean-Claude Bradley, at 6:39 AM  

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