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Topic: alkylation of alkyne  (Read 8561 times)

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Offline viet

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alkylation of alkyne
« on: April 02, 2010, 07:13:13 PM »
can someone check if this is right? i'm suppose to write the structural formula for this reaction.

CH3CH2CH2CCH  1.NaNH2/2.CH3CH2CH2Br :rarrow:

I got the answer: CH3CH2CH2CCCH2CH2CH3

Offline Jorriss

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Re: alkylation of alkyne
« Reply #1 on: April 02, 2010, 09:14:37 PM »
can someone check if this is right? i'm suppose to write the structural formula for this reaction.

CH3CH2CH2CCH  1.NaNH2/2.CH3CH2CH2Br :rarrow:

I got the answer: CH3CH2CH2CCCH2CH2CH3
Yup, that looks good.

Offline bromidewind

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Re: alkylation of alkyne
« Reply #2 on: April 03, 2010, 12:17:46 AM »
You got it except for two minor things.
1. It's Na/NH3, not NH2.
2. If asked, be sure you remember the anti- stereochemistry that the hydrogens add by. The resulting alkene will take on a trans- configuration rather than cis-.

Offline dunno260

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Re: alkylation of alkyne
« Reply #3 on: April 03, 2010, 04:58:50 AM »
It is NaNH2 and not Na/NH3 which would reduce the alkyne to an alkene.  You want a strong base to deprotonate the alkyne to create the nucleophilic alkyne and sodium amide is the one that is typically given in undergrad O Chem textbooks.

Offline viet

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Re: alkylation of alkyne
« Reply #4 on: April 05, 2010, 09:59:16 AM »
thanks guys

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