Question

This is the Wittig reaction (synthesis to make E and Z stilbenes)

This is for the Wittig Lab of Organic Chemistry 2. Please answer to all 3 questions with explanations as simple and specific and possible to understand.

(CgHs)3РСH,CoH,Cr, NaOH H CH2CI2 What happens when NaOH is added to the reaction mixture? Draw the species formed and any reasonable resonance form(s). 10 pts 1. Once the reaction mixture is added to a test tube and dichloromethane (DCM) is added, why is a sodium bisulfite wash performed? (10 pts) 2. After the bisulfite is added, what is the predominate solute in the organic layer and aqueous layer? Draw a sketch of the test tube showing the two layers and the solutes. (10 pts) Show the carbonyl compound and ylide needed to produce the following. (20 pts) 3.

Answer 1

Ph Ph Ph Ph Ph Ph Ph Na+:OH Ph Ph Ph Ph Ph P-Ylide 1) When we add NaOH to reaction mixture it gives phosphurus ylide as shown above 2) Unreacted benzaldehyde is removed by forming bisulfite adduct. Which is solid and can be seprated by simple partition OH CHO "SO3Na NaHSO3 solid bisulfite adduct is formed 3) Bilsulfite is in the aqueous layer and stilbene is in the DCM layer. Water bisulfite adduct DCM stilbene

Each alkene can have two carbonyls possible however, here l am showing only one of that as an answer Ph3P CHз cyclohexanone CHз CHз PhgP, CH2 CH2 Нас Ma 2-methylpent-1-ene Hзс pentan-2-one PPH3 CH3 Hас- propan-2-one PPH3 Hас Нас 1-methylcyclohex-1-ene