Which of the following best describes the product formed when an $\mathrm{aldehyde}$ reacts with a $\mathrm{phosphonium}\mathrm{ylide}$ in a $\mathrm{Wittig}$ reaction?

Show how you would accomplish the following syntheses efficiently and in good yield. You may use any necessary reagents.

(e)

Show how you would accomplish the following synthetic conversions efficiently and in good yield. You may use any necessary additional reagents and solvents.

(h)

What two sets of reagents (each consisting of a carbonyl compound and phosphonium ylide) can be used for the synthesis of the following alkene?

1.

Suggest the appropriate carbonyl and Wittig reagent to make the following alkenes.

a. (E)-7-methylnon-4-en-3-one

Determine the carbonyl and ylide that formed the following product.

Trimethylphosphine is a stronger nucleophile than triphenylphosphine, but it is rarely used to make ylides. Why is trimethylphosphine unsuitable for making most phosphorus ylides?

Propose mechanisms for the following reactions.

(c)