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The Chemical Educator
ISSN: 1430-4171 (electronic version)
Abstract Volume 27
(2022) pp 60-64
Synthesis of the Natural Product E-Anethole From Anisole: A Multistep Synthesis Experiment for Second-Year Undergraduate Organic Laboratory
Brant L. Kedrowski * and Micaela Villaire
Department of Chemistry, University of Wisconsin Oshkosh, Oshkosh, WI, 54901, kedrowsk@uwosh.edu
Received January 5, 2021. Accepted May 13, 2021
Published: 19 November 2022
Abstract. A multistep synthesis of E-anethole is described as a multi-week experiment for the undergraduate organic laboratory curriculum. The target molecule is a natural product that is present in several common spices and has an aroma that will be familiar to most students. The procedure utilizes reactions that are commonly covered as part of a standard second year organic chemistry curriculum. This can serve to reinforce lecture content in lab and lab content in lecture. The experiment starts with anisole and proceeds through three synthetic steps that include Friedel-Crafts acylation in step one, ketone reduction in step two, and alcohol dehydration in step three. The reactions provide opportunities for discussions about regioselectivity and stereoselectivity at each step. The procedure produces a 14:1 or greater molar ratio of E- and Z-anethole. Yields in the sequence are good to moderate and the reactions are complete in less than 30 minutes. Additionally, intermediates are isolated as pure substances that can be characterized without the need for time-consuming purifications. This enables the three-step synthetic sequence to be comfortably completed within two 3 h lab periods along with characterization of substances using IR spectroscopy, NMR spectroscopy, and gas chromatography. The experiment was carried out during the second semester of a standard yearlong organic chemistry sequence and student results are described.
Key Words: KW Laboratories and Demonstrations; , Undergraduate Organic Chemistry; Aromatic Compounds; Friedel-Crafts Acylation; Carbonyl Reduction; Alcohol Dehydration; Stereochemistry; Multistep Synthesis; IR Spectroscopy; NMR Spectroscopy, Gas; Chromatography
onding author. (E-mail: kedrowsk@uwosh.edu)
Article in PDF format(207KB) HTML
A list of information for chemicals used is provided that includes chemical names, condensed structural formulas, CAS numbers, and GHS hazard statements. Detailed experimental procedures and characterization data for steps 1–3 are provided . Copies of FTIR, 1H NMR, 13C NMR, HSQC, HMBC spectra for all compounds as well as a gas chromatogram for the final product mixture are provided (Safety_Experimental_&_ Characterization.pdf). 2214 KB
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