Question

Draw the product formed by the reaction of t-butoxide with (1R,2S)-1-bromo-2-methyl-1-phenylbutane (shown below). Draw the correct stereoisomer of the product. Draw the product as a skeletal structure. H, Br (CH3),coºk* (CH3),COH Hzclllll CH2 H3C/ Previous Check Answer Next Exit

Answer 1

The answer is given in the attachment.

Answer Ph H 14 -Ph (49 Sawhorse Djectim ph Co l4 anti periplamer Tmitn stul bar riantation Elinumalim *n CE allkene

Answer 2

Concepts and reason

• Organic reactions are classified into four types: addition, substitution, elimination, and rearrangement reactions.

• Based on the structure of the reactant and the nature of reagent, the mechanism in an elimination reaction goes through either an E1 or E2 pathway.

• An E2 elimination reaction is a bimolecular elimination reaction.

• This elimination process is a single-step process that follows the concerted way mechanism.

• In an E2 elimination reaction, the intermediate is in a transition state.

• The rate of the reaction depends on both the base and the substrate.

• Examples of elimination reactions are:

i)Dehydration

ii)Dehydrohalogenation

iii)Dehydrogenation

Fundamentals

The general scheme for an elimination reaction is depicted below:

In an elimination reaction, the structure of the alkene product formed depends on the nature of the base (bulkier or lighter) used in the reaction to attract the acidic proton in the substrate. If a bulky base is used, a Hoffman product is formed; and if the base is not sterically hindered, then a highly substituted alkene is the product formed according to the Zaitsev’s rule.

Hoffman rule: Due to steric hindrance of the bulky base, the least substituted alkene is preferred.

Zaitsev’s rule: The most substituted double bond in an alkene is more stable, if the base used is not steric hindered.

The given base is ${\left( {{\rm{C}}{{\rm{H}}_{\rm{3}}}} \right)_{\rm{3}}}{\rm{, C}}{{\rm{O}}^{\rm{ - }}}{{\rm{K}}^{\rm{ + }}}\left( {{\rm{potassium tert}} - {\rm{butoxide}}} \right)$ which reacts with alkyl halide; the mechanism is given below:

The product formed from the transition state is given below:

Ans:

The product formed by the reaction of t-butoxide with $\left( {1R,2S} \right){\rm{ - 1 - bromo - }}$ ${\rm{2 - methyl - 1 - phenylbutane}}$ is given below: