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Why NaBH4 is used as reducing agent?

Sodium borohydride NaBH4 is less reactive than LiAlH4 but is otherwise similar. It is only powerful enough to reduce aldehydes, ketones and acid chlorides to alcohols: esters, amides, acids and nitriles are largely untouched. It can also behave as a nucleophile toward halides and epoxides.

What is the work of NaBH4?

The principal application of sodium borohydride is the production of sodium dithionite from sulfur dioxide: Sodium dithionite is used as a bleaching agent for wood pulp and in the dyeing industry. Sodium borohydride reduces aldehydes and ketones to give the related alcohols.

Does NaBH4 reduce or oxidize?

Sodium borohydride (NaBH4) is a mild reducing agent. It is only capable of reducing aldehydes and ketones to alcohols. Chromate (LiAlH4) is a strong oxidizing agent; it oxidizes primary alcohols all the way to carboxylic acids, and secondary alcohols to ketones. Cannot be oxidized further.

Does NaBH4 reduce Cinnamaldehyde?

Sodium borohydride reduces cinnamaldehyde via 1,2-reduction in hydroxylic solvent to cinnamyl alcohol in 97% yield.

Can NaBH4 reduce imine?

Sodium borohydride: NaBH4 Also effective for reducing imines.

Can NaBH4 reduce carboxylic acid?

What it’s used for: Sodium borohydride is a good reducing agent. By itself, it will generally not reduce esters, carboxylic acids, or amides (although it will reduce acyl chlorides to alcohols).

Why NaBH4 does not reduce carboxylic acid?

Now considering the mechanism, due to the small polarity induced by the carbonyl group of the carboxylic acid, the H atom in Al−H bond is readily broken due to its high polarity, while the H in B−H can’t do the same because it has a low polarity.

Which of the following compound reduces by NaBH4?

Aldehydes and ketones are easily reduced by sodium borohydride (NaBH4).

Does NaBH4 reduce carboxylic acids?

Standard organic chemistry texts discuss the lower re- activity of NaBH4 compared with lithium aluminum hy- dride, LiAlH4: whereas LiAlH4 reduces carboxylic acids to primary alcohols, NaBH4 does not reduce carboxylic acids.

What is the mechanism for a NABH 4 reduction?

LiAlH 4 and NaBH 4 are both capable of reducing aldehydes and ketones to the corresponding alcohol. This mechanism is for a LiAlH 4 reduction. The mechanism for a NaBH 4 reduction is the same except methanol is the proton source used in the second step.

How does sodium borohydride reduce aldehydes and ketones?

Sodium borohydride reduces aldehydes and ketones by a similar mechanism with some important differences that we need to mention. First, NaBH4 is not so reactive and the reaction is usually carried out in protic solvents such as ethanol or methanol.

Why are stereoisomers produced by LiAlH4 and NaBH4?

The reduction of unsymmetrical ketones with LiAlH4 or NaBH4 produces a pair of stereoisomers because the hydride ion can attack either face of the planar carbonyl group: If no other chiral center are present, the product is a racemic mixture of enantiomers.

How is methanol used in metal hydride reduction?

In metal hydrides reductions the resulting alkoxide salts are insoluble and need to be hydrolyzed (with care) before the alcohol product can be isolated. In the sodium borohydride reduction the methanol solvent system achieves this hydrolysis automatically. In the lithium aluminium hydride reduction water is usually added in a second step.