1) When you do the Wittig-Horner reaction, you will become quite aware of the stench of one of the reagents used. Also, two are suspected carcinogens and toxic, one liquid and one solid is flammable, one is only a mild irritant and actually smells good, and one is a flammable solid which also reacts violently with water. Therefore, it is essential that you work with extreme care so as not to spread these chemicals around the lab by spilling or rinsing glassware into the sinks, and you must keep your hood faces down and cover containers as you travel through the room. Which of the following statements is true?
2) Consider the two compounds below. Which is a phosphite and which is a phosphine?
3) The first step in a Wittig reaction is the reaction of triphenyl phosphine with an alkyl halide to produce a phosphonium salt. Give the products of the following reaction to form a phosphonium salt. (Draw your compounds, state whether you think you are right or wrong, then check your answer.)
Answer to question 3.
4) At what point in the Wittig Horner reaction will you add the base, sodium methoxide?
5) Draw the structure of the reaction of the following phosphonium salt with strong base (BuLi).
Answer to question 5.
6) Starting with triphenyl phosphine and any desired alkyl halide, aldehyde, and ketone, show how the following alkene can be prepared via a Wittig synthesis:*
Answer to question 6.
*Hint: Wittig reactions make an alkene from an aldehyde or ketone plus an alkyl halide, replacing the oxygen and the halide by a double bond. Here is an excellent Web site link to help explain (University of Sunderland in the UK.)
