Synthesis of Methyl Cyclopentanecarboxylate: A Laboratory Experience in Carbon Rearrangement

Abstract

We present a novel guided inquiry second semester organic chemistry laboratory rearrangement experiment. Students performed the Favorskii Rearrangement to obtain methyl cyclopentanecarboxylate in good yields. The students learned about the individual steps of the Favorskii mechanism and were required to propose a complete reaction mechanism and product structure. The students then confirmed the structure of the product by NMR and IR spectroscopy. This experiment provides students with experience in running organic chemistry reactions, structure determination, spectroscopy, general problem solving, and drawing rearrangement mechanisms.

Introducing Regioselectivity in Rearrangement Reactions through a Discovery Experiment Using an Improved Schmidt-Type Reaction

“…To enhance understanding, hands-on experimentation is recommended to render these concepts tangible. 9 Although experimental designs for rearrangement reactions have been introduced into laboratory education, such as Favorskii rearrangement, 10,11 Hofmann rearrangement, 12 Fries rearrangement, 13 and Pinacol rearrangement, 14 discussions on the regional selectivity of rearrangement reactions remain sparse. Therefore, the introduction of a regioselective rearrangement reaction into undergraduate experimental education holds profound importance.…”

“…Among them, regioselectivity, which is a feature of most rearrangement reactions involving asymmetric substrates, occupies an important position in organic chemistry curricula (Figure b). To enhance understanding, hands-on experimentation is recommended to render these concepts tangible …”

Expanding the Scope of an Electrophilic Aromatic Substitution Discovery Experiment Including Hydride and Methyl Shifts

“…Salzameda and co-workers explored the Favorskii rearrangement in the synthesis of methyl cyclopentanecarboxylate. 34 Two groups independently presented a valuable update to the classic dehydration of 2-methyl-cyclohexanol laboratory, including an examination of the formation of five previously unidentified products via carbocation rearrangements. The mechanisms include both hydride and alkyl shifts, including a ring contraction.…”

“…However, among the many reactions that have been explored in the undergraduate laboratory, only a handful of experiments involve carbocation rearrangements. Salzameda and co-workers explored the Favorskii rearrangement in the synthesis of methyl cyclopentanecarboxylate . Two groups independently presented a valuable update to the classic dehydration of 2-methyl-cyclohexanol laboratory, including an examination of the formation of five previously unidentified products via carbocation rearrangements.…”

Discovery-Based Bromination of Alcohols: An Organic Chemistry Experiment Supporting Spectroscopic Analysis and Mechanistic Reasoning

“…During these experiments, therefore, the students must “discover” the experimental outcome once they have obtained the necessary data. Some survey and assessment data have indicated that discovery-based approaches may lead to greater laboratory enjoyment, a sense of achievement, and better learning outcomes. − As such, many discovery-based laboratories − have been developed in the past few decades to replace more traditional expository experiments, where students simply verify expected experimental outcomes.…”