Q.11-15P - Organic Chemistry (Mcmurry)

Question

Question: Ignoring double-bond stereochemistry, what products would you expect from elimination reactions of the following alkyl halides? Which product will be the major product in each case?

Step-by-Step Solution

Answer

Answer

                                                     Major                                        minor

Step 1: Zaitsev’s rule

Zaitsevs rule predicts that in an elimination reaction, the most substituted product will be the most stable, and therefore the most favored. The rule makes no generalization about the stereochemistry of the newly formed alkene, but only the regiochemistry of the elimination reaction.

Step 2: Determine product from elimination reactions of the following alkyl halides

Form the double bond by removing HX from the alkyl halide reactant in as many ways as possible. The major elimination product in each case has the most substituted double bond (Zaitsev’s rule).

 

(a)

 Add one more step, write about elimination reactions

                                                                  Major                                        minor

(trisubstituted double bond)         (disubstituteddoublebond)                

 (b)

(c)

(trisubstituted double bond)(monosubstituteddoublebond)