Question

The Wittig Reaction 1. Complete the following reactions by filling in the blanks with the correct structures. (15 pts) NaOH PPhy COOH The scheme above is the reaction you were supposed to perform today. Answer the following question pertaining to the experiment (page 43-44). (a) The first reaction was run in acetone and the product filtered (we can instead, just remove the acetone on the rotary evaporator). What is the product? (5 pts) (b) The product obtained in part 1 was added to formaldehyde followed by aqueous sodium hydroxide and stirred. After the reaction, a solid was filtered and discarded. What is the solid? (5 pts) (c) The filtrate was acidified with HCl until pH 1, which resulted in precipitation of the product, that was collected by suction filtration. Explain this process (solubility to insolubility) using chemical equations. (5 pts) (d) The product was to be characterized using KMnO4 Show the reaction that takes place between a double bond and an alkene. (5 pts) (e) Provide a mechanism for the Wittig reaction (The reaction between the formaldehyde and the ylide) (5pts)

Answer 1

solution: o PPha ophy N LA 0 | [ ] C0 0 | 0 0 0 | 0 0 Klittig salt telides Yilde. CH 2 klittig reaction. | _ | C00 , ppha Ppha Acetor Сои 0 0 | The product is wittig salto D Peha ( LH Naol ૦ 0 H. The solist solidis is sodium salt of H | styrene. The comp sodium salt of styrene is acidity with Hd up to pH-I. He will get free acid of styrener [ L. pH-1 I COOH t ao na 0H Ho . Y King & 46 X The cellene reacts with knonoy to form diol. The de colourisation of knnoy. 5 . | C0 0 | ૮૦૦+

Mechanismi Kly opphs - PPhz o PPha [-] coon COOH COOH Betaine Vilde oxaphosphetane Felide I t o=p Phz TPPO Tripheryl Cool phosphinc oxide