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Does DIBAL-H reduce carboxylic acids?
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Mario Festus
Does DIBAL-H reduce carboxylic acids?
Does diisobutylaluminium hydride (DIBAL-H) reduce only carboxylic acids? or only carboxylic acid esters? or reduce both both types of compounds?
The answer is yes, it does reduce both. Not only them, it also reduces nitriles to aldehydes, and is a more selective reagent than lithium aluminum hydride (LAH) in the reduction of nitriles (Ref.1). About reduction of carbozylic acid, Miller et al. (Ref.1) found that DIBAL-H can be used to reduce benzoic acid to give 72% yields of benzyl alcohol in 1959. In same publication, they have also shown that esters can be reduced to corresponding alcohols as well.
In reduction of nitriles to aldehydes, following results were achieved and compared with the result obtained by Amundsen and Nelson (Ref.2) using $\ce{LiAlH4}$:
The summery of reduction of carboxylic acids and their esters are illustrated in following scheme, where two different groups (Ref.1 & Ref.3) achieved two different results for ester reduction under different conditions:
References:
A. E. G. Miller, J. W. Biss, and L. H. Schwartzman, “Reductions with Dialkylaluminum Hydrides,” J. Org. Chem.1959, 24(5), 627–630 (DOI: 10.1021/jo01087a013).
L. H. Amundsen, L. S. Nelson, “Reduction of Nitriles to Primary Amines with Lithium Aluminum Hydride,” J. Am. Chem. Soc.1951, 73(1), 242–244 (DOI: 10.1021/ja01145a082).
L. I. Zakharkin, I. M. Khorlina, “Reduction of esters of carboxylic acids directly into aldehydes with diisobutylaluminum hydride,” Tetrahedron Letters1962, (14), 619-620 (https://doi.org/10.1016/S0040-4039(00)70918-X).
Does diisobutylaluminium hydride (DIBAL-H) reduce only carboxylic acids? or only carboxylic acid esters? or reduce both both types of compounds?
The answer is yes, it does reduce both. Not only them, it also reduces nitriles to aldehydes, and is a more selective reagent than lithium aluminum hydride (LAH) in the reduction of nitriles (Ref.1). About reduction of carbozylic acid, Miller et al. (Ref.1) found that DIBAL-H can be used to reduce benzoic acid to give 72% yields of benzyl alcohol in 1959. In same publication, they have also shown that esters can be reduced to corresponding alcohols as well.
In reduction of nitriles to aldehydes, following results were achieved and compared with the result obtained by Amundsen and Nelson (Ref.2) using $\ce{LiAlH4}$:
The summery of reduction of carboxylic acids and their esters are illustrated in following scheme, where two different groups (Ref.1 & Ref.3) achieved two different results for ester reduction under different conditions:
References:
A. E. G. Miller, J. W. Biss, and L. H. Schwartzman, “Reductions with Dialkylaluminum Hydrides,” J. Org. Chem.1959, 24(5), 627–630 (DOI: 10.1021/jo01087a013).
L. H. Amundsen, L. S. Nelson, “Reduction of Nitriles to Primary Amines with Lithium Aluminum Hydride,” J. Am. Chem. Soc.1951, 73(1), 242–244 (DOI: 10.1021/ja01145a082).
L. I. Zakharkin, I. M. Khorlina, “Reduction of esters of carboxylic acids directly into aldehydes with diisobutylaluminum hydride,” Tetrahedron Letters1962, (14), 619-620 (https://doi.org/10.1016/S0040-4039(00)70918-X).
My book (Cengage for JEE Adv) doesn't mention anything about carb acids, but I was able to find this website that says DiBAL-H reduces carb acids to aldehydes and alcohols, but requires 2-3 equivalents, at a high temperature.
My book (Cengage for JEE Adv) doesn't mention anything about carb acids, but I was able to find this website that says DiBAL-H reduces carb acids to aldehydes and alcohols, but requires 2-3 equivalents, at a high temperature.
Why DIBAL is weaker than LiAlH4 . as per mechanism mentioned in the site https://www.entrancei.com/questions-lialh4-reaction-and-mechanism
LiAlH4 is H- Donor , the RDS is H- release if we take DIBAL it consist of two electron donating group makes it e rich so i think it can donate H- faster than LiAlH4 . secondly i have seen in many book it can reduce all functional group which are reduce by LAH .
Why DIBAL is weaker than LiAlH4 . as per mechanism mentioned in the site https://www.entrancei.com/questions-lialh4-reaction-and-mechanismLiAlH4 is H- Donor , the RDS is H- release if we take DIBAL it consist of two electron donating group makes it e rich so i think it can donate H- faster than LiAlH4 . secondly i have seen in many book it can reduce all functional group which are reduce by LAH .
Does diisobutylaluminium hydride (DIBAL-H) reduce only carboxylic acids? or only carboxylic acid esters? or reduce both both types of compounds?
The answer is yes, it does reduce both. Not only them, it also reduces nitriles to aldehydes, and is a more selective reagent than lithium aluminum hydride (LAH) in the reduction of nitriles (Ref.1). About reduction of carbozylic acid, Miller et al. (Ref.1) found that DIBAL-H can be used to reduce benzoic acid to give 72% yields of benzyl alcohol in 1959. In same publication, they have also shown that esters can be reduced to corresponding alcohols as well.
In reduction of nitriles to aldehydes, following results were achieved and compared with the result obtained by Amundsen and Nelson (Ref.2) using $\ce{LiAlH4}$:
The summery of reduction of carboxylic acids and their esters are illustrated in following scheme, where two different groups (Ref.1 & Ref.3) achieved two different results for ester reduction under different conditions:
References:
Does diisobutylaluminium hydride (DIBAL-H) reduce only carboxylic acids? or only carboxylic acid esters? or reduce both both types of compounds?
The answer is yes, it does reduce both. Not only them, it also reduces nitriles to aldehydes, and is a more selective reagent than lithium aluminum hydride (LAH) in the reduction of nitriles (Ref.1). About reduction of carbozylic acid, Miller et al. (Ref.1) found that DIBAL-H can be used to reduce benzoic acid to give 72% yields of benzyl alcohol in 1959. In same publication, they have also shown that esters can be reduced to corresponding alcohols as well.
In reduction of nitriles to aldehydes, following results were achieved and compared with the result obtained by Amundsen and Nelson (Ref.2) using $\ce{LiAlH4}$:
The summery of reduction of carboxylic acids and their esters are illustrated in following scheme, where two different groups (Ref.1 & Ref.3) achieved two different results for ester reduction under different conditions:
References:
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My book (Cengage for JEE Adv) doesn't mention anything about carb acids, but I was able to find this website that says DiBAL-H reduces carb acids to aldehydes and alcohols, but requires 2-3 equivalents, at a high temperature.
My book (Cengage for JEE Adv) doesn't mention anything about carb acids, but I was able to find this website that says DiBAL-H reduces carb acids to aldehydes and alcohols, but requires 2-3 equivalents, at a high temperature.
More
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Why DIBAL is weaker than LiAlH4 . as per mechanism mentioned in the site https://www.entrancei.com/questions-lialh4-reaction-and-mechanism LiAlH4 is H- Donor , the RDS is H- release if we take DIBAL it consist of two electron donating group makes it e rich so i think it can donate H- faster than LiAlH4 . secondly i have seen in many book it can reduce all functional group which are reduce by LAH .
Why DIBAL is weaker than LiAlH4 . as per mechanism mentioned in the site https://www.entrancei.com/questions-lialh4-reaction-and-mechanismLiAlH4 is H- Donor , the RDS is H- release if we take DIBAL it consist of two electron donating group makes it e rich so i think it can donate H- faster than LiAlH4 . secondly i have seen in many book it can reduce all functional group which are reduce by LAH .
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