Name: p-block Elements
Uploaded: 2019-07-19
Duration: 2 min 38 s
Description: Do you know why some elements of the periodic table are known as p-block elements? Learn about p-block elements and their general properties in this video.

Question

Describe the use of diborane in hydroboration.

Accepted Answer

A very important reaction takes place between Diborane and alkenes, alkynes.This reaction are carried out in dry ether conditions. This reaction takes place in a di nitrogen condition as the products are very reactive.

$\frac{1}{2} B_{2} H_{6} + 3 RCH = CHR \to B ({CH}_{2} - {CH}_{2} R)_{3} \frac{1}{2} B_{2} H_{6} + 3 RC \equiv R \to B (RC = CHR)_{3}$

The alkyl borane products are not usually isolated.They are converted as:

1. When treated with carboxylic acids forms hydrocarbons.

2. To alcohols by reaction with alkaline $H_{2} O_{2}$ .

${BR}_{3} + 3 {CH}_{3} COOH \to 3 RH + B ({CH}_{3} COO)_{3}$

$B ({CH}_{2} . {CH}_{2} R)_{3} + H_{2} O_{2} \to 3 {RCH}_{2} {CH}_{2} OH + H_{3} {BO}_{3}$

The reaction takes place in an Anti-Markovnikov manner, where the hydrogen (from ${BH}_{3}$ or ${BHR}_{2}$ ) attaches to more substituted carbon and the boron attaches to the least substituted carbon in the double bond.

Describe the use of diborane in hydroboration.

Important Questions on The Group 13 Elements

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