Question

Provide the major product of the following reaction sequence. If cis/trans is possible, draw only the major isomer. If enantiomers are possible, do not specify configuration.

Answer 1

Concepts and reason

A reaction is given with the reagents whose correct product needs to be drawn. In the given reaction, a diene is undergoing an electrophilic substitution reaction with bromine. Draw the correct substitution product by considering the reaction conditions, that is, temperature as it will result in the formation of different products.

Fundamentals

Diene are generally considered as good source of electron due to presence of $4{\rm{\pi }}$ electrons. Therefore, dienes show electrophilic addition reaction and depending on the reaction condition results in the formation two addition product as shown below:

Draw the product of the reaction by the addition of bromine to the butadiene molecule as shown below:

Draw the final product of the attack of cyanide ion on the product formed in step 1 as shown below:

Ans:

Hence, the final product of the given reaction is as follows:

Answer 2

Answer 3

When the 1,3-butadiene is reacted with bromine it gives 1,4 addition product in presence of greater amountsf heat.This on further reacted with 2 equivalents of NaCN in the presence of DMF gives the corresponding substitution product. 1) Br2, heat buta-1,3-diene 2) 2 equiv NaCN, DMF