Master of Science (MS)
Semester of Degree Completion
T. Howard Black
In connection with the continuing interests in the stereoselective rearrangements of β-lactones, an investigation of the synthesis and transformations of the epoxy β-lactone 4-(1,2-epoxypentyl)-3-trimethylsilyloxetan-2-one was undertaken. Two synthetic strategies to the desired epoxy β-lactone were studied. The first route was a two-step reaction sequence involving the aldol reaction of trimethylsilylacetic acid with (2R,3S)-epoxyhexanal, followed by lactonization of the resulting β-hydroxy acid with benzenesulfonyl chloride. Complications in preparing the requisite β-hydroxy acids under typical aldol reaction conditions rendered this route unworkable. The complexity and intractability of the aldol reaction mixtures was attributed to the multiple possibilities of intermolecular reactivity between trimethylsilylacetic acid dianion and (2S,3S)-epoxyhexanal, in addition to intramolecular transformations of the highly functionalized aldol adduct. The second synthetic route investigated was based on the [2+2] cycloaddition reaction between trimethylsilylketene and (2R,3S)-epoxyhexanal. No direct evidence supporting the formation of epoxy β-lactone was found; however, the formation of the 5-(1-O-trimethylsilylpropyl)-2-(5H)-furanone suggests that the desired epoxy β-lactone was formed but was unstable under the [2+2] reaction conditions. Literature precedence supports this contention, and a thorough literature investigation was conducted with the purpose of elucidating possible transformations of the epoxy β-lactone.
Farrell, John, "Investigations into the Synthesis and Transformations of an Epoxy β-Lactone" (2000). Masters Theses. 1567.