During my synthesis of anhydro levuglandin D2 I had to reduce a lactone to an aldehyde. All my attempts with DIBAL were failures (no reaction), but the "ate" complex formed from DIBAL and tert-Butyl Lithium gave a reagent that allowed me to control the amount of reducing agent that I added and provided the desired compound (the open ring aldehyde) in decent yields. See links.

http://ac.els-cdn.com/S0040403900840691/1-s2.0-S0040403900840691-main.pdf?_tid=4e9a741e-7063-11e6-857d-00000aab0f26&acdnat=1472748430_0972e6dfb9212c8e1cf6fdb77ff8d8b9

http://www.sciencedirect.com/science/article/pii/S0040403901912195

it is sometimes easier to just reduce down to the alcohol and selectively oxidise back to the aldehyde. There are more reagents to do the selective oxidation then do selective reduction. 

I used DIBAL at -78oC before but the ester and aldehyde is very close on TLC and difficult to monitor. NMR or LCMS are possible alternatives but still troublesome 

Try to use lithium diisobutyl-tert-butoxyaluminium hydride (LDBBA). One of the protocols for obtaining the reagent you find in work Kim et al. Tetrahedron Lett 48 (2007) 5061-5064, Reference and notes: 8. 

Dear Matheus Andrade Meirelles

You need to detect the products using NMR and see if you obtained alcohol and beside aldehyde or not and if so, how much percent alcohol you get and then you can decide if this method is suitable or not.

Thank a lot guys. I checked by NMR and after 4 hours of reaction, even after adding 3eq. of DIBAL I still have a lot of starting material and about 20% of aldehyde. I may try other condition for this reaction, if those don't work, I'll try something different. Eugene, at first I was thinking of doing the 2 steps, reduction to alcohol and oxidation to aldehyde. However, I found a paper that uses this methodology with morpholine and I got curious on that.

Bruce and Adam, thank for the suggestions, I may try it.

Yes, you need a new method. I think you may try Eugene suggestion to reduce down to the alcohol and selectively oxidise back to the aldehyde.

According to my experience, in this type reduction controlling the reaction condition (particularly temperature) is extremely important. Depending on the reactivity of your ester, the optimal temperature can vary from -60 C to -30 C, but it is still difficult to get the aldehyde exclusively. 

Also, you need to be careful during the workup procedure since even moderate increase in temperature when the excess of DIBAL is not completely destroyed, may give the over reduction product (alcohol). For the same reason TLC is not a suitable method for monitoring the reaction progress - the overreduction can occur when you are taking a sample for analysis.

Reduction of  an Ester to aldehyde can be achieved  by partial reduction of ester by sodium in ethanol, 

Diisobutylaluminium Hydride (DIBALH), very widely used reducing agent especially for reducing esters esters can be reduced to either the aldehyde or the alcohol depending on the stoichiometry and reaction conditions:

Using 2eqv.  of  DIBALH lead to the formation of alcohol, however, using 1 eqv. DIBALH at -78 0C in toluene lead to the formation of aldehyde only.

See the full ppt. on Reduction Reactions, by: Prof. Dr. Burkhard König, Institut für Organische Chemie, Uni Regensburg

Dear Madhukar,

Using of sodium in ethanol in reduction of ester known as Bouveault–Blanc reduction leading to the formation of alcohol.

https://www.google.com.eg/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwjV96z6t5bPAhVKBcAKHQvLCS8QFgg0MAI&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FCarbonyl_reduction&usg=AFQjCNGavtqCiE5XChUHpYp6fCdkhOUCYg

Best regards

 Matheus Andrade Meirelles

Have a look at

A Synthesis of trans-beta-Farnesene from Myrcene which          includes a Modified Work Up Method for DIBAH Reductions of          Esters to Aldehydes     

P.Baeckström, L.Lee, M.Wickramaratne and T.Norin     

Synthetic Communications (1990)

My method might solve your problem. 

Dear Prof. Peter Baeckström

Would you please, send us your nice interested paper (P.Baeckström, L.Lee, M.Wickramaratne and T.Norin     Synthetic Communications (1990).

Best regards

I could accomplish the reduction of ester to the aldehyde by reducing the ester to alcohol (98% yield) using DIBAL-H, then oxidizing the alcohol to aldehyde using MnO2. I'm still looking for some methods in order to avoid those two steps and go directly from ester to aldehyde.

Could you please send us your paper Dr. Baeckström?

Matheus Andrade Meirelles

Unfortunately I don’t have the full text to send from the computer. You will have to find my article in a library. 

Best regards 

Peter

Dear Prof. Peter Baeckström,

As you mentioned, the full text of the paper isn't found in your library. Do you've the volume and page numbers?.

Hello,

I use mno2 in chloroform to oxidize alcohol to aldehyde but the reaction no longer works.

Could any one help me.

Thanks

us Red-Al R ef bull Korean Chem Soc 2014 , vol 35 (7) 2169

At a low temperatures (-78oC),  the reduction of esters with 1 equiv. of DIBAL-H gives aldehyde . This is because the transfer of one hydride to the carbonyl carbon of ester ,leads to the formation of the tetrahedral intermediate stable at low temperature.

I am going to do the reduction of ester in a few weeks the information is very useful tank you very much. My question is how to work up the reaction before separating?

Madhukar Baburao Deshmukh

Madhukar Baburao Deshmukh this is indeed a great method. However, my experience suggests that if we are dealing with an α,β-unsaturated ester, this method also gives a mixture of aldehyde and the corresponding alcohol. Bathabile Makhathini Methanol should be added dropwise at -78°C to quench the excess of DIBAL. Then, water can be added very slowly to the final quench. Aluminum salt will precipitate and before extracting the aqueous phase with organic solvents, you can add Rochelle salt (Potassium sodium tartrate) and stir the solution for couple of hours (I usually stir it for 3 hours). This will disrupt the aluminum salt and facilitates the extraction. If your compound is stable in acidic conditions, you can use aqueous acid to work-up disrupt the aluminum salts too. Then, you can extract the aqueous phase.

plz read this article:

DOI : http://dx.doi.org/10.5012/bkcs.2014.35.7.2169