The Mitsunobu reaction is a vital name reaction in the synthesis of many large-scale compounds due to its stereospecificity. However, the reaction may reach maximum yield at an average of seven days. Previously published works indicate the use of sonication speeds up the reaction to less than one hour with a majority of the yield accumulating in the first fifteen minutes. The sonicated Mitsunobu reaction with benzoic acid and (-) menthol forms four diastereomers in unequal concentrations. This is indicative of an alternative or competing mechanism, possibly free radical or ionic. Further research is being conducted to study the reaction rates of deuterated versus non-deuterated starting materials. The goal of this research project is to provide support for the existence of a kinetic isotope effect (KIE). By probing the rates of the sonicated Mitsunobu reaction, the role of the bond between the most acidic hydrogen/deuterium and the oxygen will be shown through the rates of each reaction. A reaction that shows a KIE&gt;1 infers that the O-D bond in question is involved in the slow step of the reaction, whereas a KIE&lt;1 infers that the alpha-carbon next to the O-D bond may play a larger role than the O-D bond itself. From this, the project will use the KIE data along with analysis of the gain/loss of products/starting materials to probe the mechanism.

Sonicated Mitsunobu reaction: Using the kinetic isotope effect for mechanistic analysis

255th National Meeting (2018)

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