Water Mediated Wittig Reactions of Aldehydes in the Teaching Laboratory: Using Sodium Bicarbonate for the in Situ Formation of Stabilized Ylides

The synthesis of alkenes using the Wittig reaction is a traditional part of many undergraduate organic chemistry teaching laboratory curricula. The aqueous medium version of the Wittig reaction presented is a reliable adaptation of this alkene formation reaction as a very safe alternative in the introductory organic chemistry laboratory. The specific aqueous Wittig reactions discussed use a one-pot reagent setup and greener methods that the students can complete within 30 min with partial workup in one laboratory period. The aqueous Wittig reactions presented have been implemented to various aldehydes and take advantage of dilute sodium bicarbonate ("baking soda") as the only base needed for in the in situ formation of stabilized ylides. Outcomes from the implementation of the proposed aqueous Wittig procedure into the organic chemistry teaching laboratory curriculum are presented. Described also are reaction workup, purification, and analysis of products using ¹H NMR and IR spectroscopy.