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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: bioengineer123 on January 25, 2015, 07:04:50 AM

Title: Reactions of Alkynes with Alkyl Halides
Post by: bioengineer123 on January 25, 2015, 07:04:50 AM
Attached is some NMR data relating to my question.

What im being asked to do:

1. Identify the compounds (which i think i have done, feel free to verify), given formula C7H14O

2. Determine what alkyl halide i could react with ethyne (and reagents of my choice) to produce either one of these compounds.

clarification of HNMR graphs:

on graph A the first signal from the left is split 3 times, second is a singlet, third is split 5 times, 4th is looks like a broad peak with up to 7 splits depending on how little of a peak you define as asplit, and the final is split 3 times.

graph B is for the most part as it looks but the integration values are alot higher.

For compound A i think 2-Heptanone makes sense.

For compound B i arrived at 2,3 Dimethylpentaldehyde.

For part 2 i would chose compound A because i think its synthesis would be simpler but this is where i have hit a roadblock. i know that you can get a ketone from an alkyne though a mercuric sulfate catalyzed hydration, but im not sure what he means by reacted with an alkyl halide, or what that alkyl halide would be because we havent talked alot about this in class yet.

I did my best to follow the rules as i saw them, if i did something wrong please let me know; otherwise i would appreciate any and all help you can provide.
(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi180.photobucket.com%2Falbums%2Fx229%2Fkukupbn%2F20150125_032626.jpg&hash=c4ad62ba8751fdbb501541675f662807a81ea17a)
(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi180.photobucket.com%2Falbums%2Fx229%2Fkukupbn%2F20150125_032612.jpg&hash=e02f7815f73eb7029c2ce778214cf5ec8dbce3f1)


Edit: cant get the images to attach, i am sure of the identification on compound A so lets more forward with my question for that one.

Mod edit: Image URLs fixed. You need to put the image URL (not the web page URL) in img tags to display an image hosted externally. Dan
Title: Re: Reactions of Alkynes with Alkyl Halides
Post by: billnotgatez on January 25, 2015, 03:25:59 PM
 + Additional Options...


When you are in the posting screen you will see this at the bottom
clicking on the plus sign gives you the ability to attach image files
note the restrictions

Allowed file types: txt, jpg, gif, pdf, png
Restrictions: 4 per post, maximum total size 5000KB, maximum individual size 2000KB

I hope this will allow you to get some assistance
Title: Re: Reactions of Alkynes with Alkyl Halides
Post by: Babcock_Hall on January 26, 2015, 06:25:17 PM
How could you get ethyne to react with an alkyl halide?  They won't react on their own, but you are given your choice of reagents.  Hint:  think in terms of nucleophiles and electrophiles.
Title: Re: Reactions of Alkynes with Alkyl Halides
Post by: Dan on January 27, 2015, 05:00:55 AM
I fixed your image URLs. You need to put the image URL (not the web page) in img tags to display an image hosted externally.

Quote from: bioengineer123 on January 25, 2015, 07:04:50 AM
For compound B i arrived at 2,3 Dimethylpentaldehyde.

It's difficult to tell because the resolution is very poor and we can't see the splitting patterns, but I don't think it's 2,3-dimethylpentanal.

Perhaps you can explain how you arrived at your answer and post better pictures of the 1H spectrum?

I agree with B = 2-heptanone