Question

The Wittig reaction is an important reaction due to the ability to form a C-C bond. Much research through the years has gone into this reaction including many studies to control the stereoselectivity. In general, the structure of the ylide is the primary thing that determines the stereoselectivity. The following phosphonium ions can be deprotonated to form ylides. Below each phosphonium ion, draw the corresponding ylide. Phot PhgP Phyp Ph3P CO CHE Ph d Phyl phop Ppppn, 2 py 2 Phir- phy the pa Pphapo Only one of the phosphonium salts would be deprotonated by NaOH. The rest require a stronger base. Why is this the case? osince Phap hat , couch is the most reactive it will not resu as strous a base to dople there is Which ylide is the most reactive? The most stable? most reactive is phat least is phill due to conjugation ... the more F selective its reaction with an aldehyde. In

Answer 1

phosphorus ylide - Phyu Phi Phapat Phyong phong phyta Przyroch p rochet Phypy ocha Phonph - Phan & Phapeph gocha This phosphonium salt will be deprotonated by HaoH because of carbonyl group (ester group) the proton is more acidic, so this phosphonium ion will get daprotonated with Noor. PhzP This phoup horous ylide is most reactive, because there is no resonace or stability for negative charge, php -OCH3 This phosphorous ylide is most stable because negative charge will be stabilised by carbonys group a