Question

Draw all stereoisomers formed when each alkene is treated with ${\mathbf{CHCl}}_{\mathbf{3}}$and $\mathbf{KOC}{\mathbf{\left(}{\mathbf{CH}}_{\mathbf{3}}\mathbf{\right)}}_{\mathbf{3}}$.

a.

b.

c.

Short answer

Answer

a.

b.

c.

Step-by-step solution

 Cyclopropane synthesis

Cyclopropanes are synthesized by the reaction of alkenes with carbene intermediates. Di-halo carbenes are reactive intermediates that would act as electrophiles in the synthesis of cyclopropane rings.

Products

a. The reaction of prop-2-ene with chloroform in the presence of potassium tert-butoxide would yield a mixture of stereoisomers. Two are achiral meso-compound, and the other two are enantiomers.

Formation of achiral meso products from cis-propan-2-ene and enantiomers from trans-propan-2-ene.

b. The reaction of but-2-ene with a di-halocarbene would yield a mixture of four identical compounds.

Formation of identical products

c. The reaction of methylcyclohex-1-ene would yield a mixture of enantiomers.

Formation of a mixture of enantiomers from methylcyclohexene.