9. Alkenes and Alkynes

What is the major product of the reaction?

What is the major product of the reaction?

What is the major product of the reaction?

When 2-bromo-3-phenylbutane is treated with sodium methoxide, two alkenes result (by E2 elimination). The Zaitsev product predominates. a. Draw the reaction, showing the major and minor products.

Predict the elimination products of the following reactions. When two alkenes are possible, predict which one will be the major product. Explain your answers, showing the degree of substitution of each double bond in the products. a. 2−bromopentane + NaOCH3 b. 3−bromo−3−methylpentane + NaOMe. (Me=methyl,CH3) c. 2-bromo-3-ethylpentane + NaOH

For each of the following alkyl halides, indicate the stereoisomer that would be obtained in greatest yield in an E2 reaction. a. 3-bromo-2,2,3-trimethylpentane