top score O chem

[utdent20]

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All of the following compounds can be reduced by LiAlH4 exccpet?
CH3CH2COOOCH3 b.CH3CH2OCH3. the following answers i knew were out.. but i figured there was no alochol being bonded in the oxirane.. so i chose that but the answer is the the last one.. any one have good explanations?

 

[PreDent2009]

Lithium Aluminum Hydride will reduce all carbonyl compounds unless its counterpart NABH4 which has some limitations. Since the first choice in actully a peroxide it can in fact reduce down the carbonyl that compound. There is nothing to reduce in the methly ethly ether so that has to be the answer. LAH reacting with alcohols is pretty hazardous and usually those two reagents are not used together because LAH is such a strong base (H-, which is comparable to a Grignard reagent) and you will actually pluck that Hydrogen off the alcohol and build up H2 gas pretty quick.

All of the following compounds can be reduced by LiAlH4 exccpet?
CH3CH2COOOCH3 b.CH3CH2OCH3. the following answers i knew were out.. but i figured there was no alochol being bonded in the oxirane.. so i chose that but the answer is the the last one.. any one have good explanations?

 

[utdent20]

I am still not fully comprehending it.. theanswer would give us a CH3CH2CH2OH?

 

[UCSD6]

the answer is actually the first one. Like predent said the LiALH4 will reduce the carbonyl to an OH group. so the end product would look like
CH3CH2COHOOCH3

The ether has no carbonyl group and therefore has nothing to reduce
hope this helps

 

[utdent20]

But the answer given is B.

 

[heatwheat]

Ya the answer IS B. The question is asking LiAlH4 will reduce everything EXCEPT... LiAlH4 reduces carbonyl groups. Since there is no carbonyl group in option b, it cannot reduce that group, making that the correct choice.

 

[DocHowell]

LiAlH4 reduces anything with a C=O basically.

In an Ether, there is no C=O, only an O which is part of the chain. So it wouldn't reduce it.

 

[utdent20]

DUHHHHH!!! i should have read the question carefully.. I GET IT>>> EXCEPT would have been key to all my questions..

 

[heatwheat]

DUHHHHH!!! i should have read the question carefully.. I GET IT>>> EXCEPT would have been key to all my questions..

Lol, don't you love it when that happens?