Comments on: Di-isobutyl Aluminum Hydride (DIBAL) For The Partial Reduction of Esters and Nitriles

By: James Ashenhurst

James Ashenhurst — Tue, 27 Aug 2024 14:01:22 +0000

In reply to Siddhesh Mandlik. Generally you start at -78 °C and let it warm from there.

By: Siddhesh Mandlik

Siddhesh Mandlik — Mon, 26 Aug 2024 03:02:26 +0000

What will be the temperature required if a reaction occurs between 3-butenenitrile and DIBAL-H to form aldehyde?

By: James Ashenhurst

James Ashenhurst — Tue, 02 Apr 2024 19:25:53 +0000

In reply to TheHegde. The acid workup? Yes, at least 3 moles of acid should be required but in practice more are often used.

By: TheHegde

TheHegde — Sat, 30 Mar 2024 13:53:37 +0000

What about the acid reduction? It requires 3 moles??

By: James Ashenhurst

James Ashenhurst — Mon, 12 Feb 2024 19:07:49 +0000

In reply to Priyanshu.

DIBAL and DIBAL-H are the same thing for our purposes.

I have never heard of DIBAL-A and have no idea what it could possibly mean.

There is such a thing as RED-Al but that’s different. https://en.wikipedia.org/wiki/Sodium_bis(2-methoxyethoxy)aluminium_hydride

By: Priyanshu

Priyanshu — Mon, 12 Feb 2024 17:28:00 +0000

I read somewhere there is DIBAL-A also just like DIBAL-H ,so please tell difference between them and also the work of DIBAL-A

By: James Ashenhurst

James Ashenhurst — Mon, 18 Dec 2023 20:07:05 +0000

In reply to RISHI V. DIBAL can in fact reduce esters to alcohols even with only one equivalent; what happens first is the conventional hydride reduction. The second reduction is a type of Meerwein-Ponndorf-Verley reduction where there is hydride transfer from the isobutyl group.

By: RISHI V

RISHI V — Sun, 17 Dec 2023 09:09:33 +0000

How can Dibal H reduce an aldehyde and a ketone to their corresponding alcohols at once which are present in a single compound but not ester to alcohol provided 1 equivalent? (Since, DIBAL H has only 1 hydride)

By: James Ashenhurst

James Ashenhurst — Sun, 10 Dec 2023 13:26:25 +0000

In reply to Sam Jo.

Hi – yes, DIBAL will do partial reduction of alpha, beta unsaturated esters to give the aldehyde. Amides too.

The alkene is untouched.

Even if the aldehyde is over-reduced to the alcohol, there are plenty of ways to go from the allylic alcohol back up to the aldehyde.

By: Sam Jo

Sam Jo — Mon, 27 Nov 2023 14:37:13 +0000

May you also expand further to include DIBAL reductions on a,b-unsaturated esters?
Do the same rules apply or do we get the alcohol?
If so, why?