Question

Draw all stereoisomers formed in each reaction.

a.

b.

c.

d.

Short answer

a.

b.

c.

d.

Step-by-step solution

Cis-trans isomerism and E-Z isomerism

Cis-trans isomerism is employed for a simple system like the disubstituted alkenes, whereas the E-Z isomerism is utilized for higher systems like the trisubstituted alkenes.

Reaction of carbonyl compounds

Carbonyl compounds get subjected to several reactions, and a critical reaction is nucleophilic addition. Cyanohydrins are formed by the nucleophilic addition of a carbonyl compound with sodium cyanide and an acid like HCl.

Predicting the stereoisomers of each reaction

a.The given compound is an aldehyde which undergoes reaction with an aldehyde leading to the formation of alkenes,(E)-oct-4-ene and (Z)-oct-4-ene. The reaction can be given as:

Stereoisomers of reaction a

b.The given compound is a ketone that undergoes nucleophilic addition with NaCN, leading to the formation of cyanohydrin. The reaction can be given as:

Stereoisomers of reaction b

c. The given reaction is a hydride reaction of a ketone. The addition of carbanions to carbonyl compounds results in the formation of a mixture of stereoisomers. The reaction can be given as:

Stereoisomers of reaction c

d. The given reaction is the reaction of a hemiacetal with an alcohol and an acid. The stereoisomers of the reaction can be given as:

Stereoisomers of reaction d