Letter pubs.acs.org/jchemeduc
Don’t Forget the Workup Andrew P. Dicks* Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6 ABSTRACT: Emphasis is placed on thoroughly considering the workup of a reaction used to promote principles of green chemistry to undergraduates. KEYWORDS: Second-Year Undergraduate, Upper-Division Undergraduate, Laboratory Instruction, Organic Chemistry, Hands-On Learning/Manipulatives, Green Chemistry, Organometallics, Synthesis a Green Suzuki Coupling Reaction. J. Chem. Educ. 2014, DOI: 10.1021/ed400498w. (3) Hill, N. J.; Bowman, M. D.; Esselman, B. J.; Byron, S. D.; Kreitinger, J.; Leadbeater, N. E. Ligand-Free Suzuki−Miyaura Coupling Reactions Using an Inexpensive Aqueous Palladium Source: A Synthetic and Computational Exercise for the Undergraduate Organic Chemistry Laboratory. J. Chem. Educ. 2014, 91, 1054−1057. (4) Hie, L.; Chang, J. J.; Garg, N. K. Nickel-Catalyzed Suzuki− Miyaura Cross-Coupling in a Green Alcohol Solvent for an Undergraduate Organic Chemistry Laboratory. J. Chem. Educ. 2014, DOI: 10.1021/ed500158p. (5) Hamilton, A. E.; Buxton, A. M.; Peeples, C. J.; Chalker, J. M. An Operationally Simple Aqueous Suzuki−Miyaura Cross-Coupling Reaction for an Undergraduate Organic Chemistry Laboratory. J. Chem. Educ. 2013, 90, 1509−1513. (6) Costa, N. E.; Pelotte, A. L.; Simard, J. M.; Syvinski, C. A.; Deveau, A. M. Discovering Green, Aqueous Suzuki Coupling Reactions: Synthesis of Ethyl (4-Phenylphenyl)acetate, a Biaryl with AntiArthritic Potential. J. Chem. Educ. 2012, 89, 1064−1067. (7) Pantess, D. A.; Rich, C. V. Aqueous Suzuki Reactions: A Greener Approach to Transition Metal-Mediated Aryl Couplings in the Organic Instructional Laboratory. Chem. Educator 2009, 14, 258−260. (8) Aktoudianakis, E.; Chan, E.; Edward, A. R.; Jarosz, I.; Lee, V.; Mui, L.; Thatipamala, S. S.; Dicks, A. P. “Greening Up” the Suzuki Reaction. J. Chem. Educ. 2008, 85, 555−557. (9) Novak, M.; Wang, Y.-T.; Ambrogio, M. W.; Chan, C. A.; Davis, H. E.; Goodwin, K. S.; Hadley, M. A.; Hall, C. M.; Herrick, A. M.; Ivanov, A. S.; Mueller, C. M.; Oh, J. J.; Soukup, R. J.; Sullivan, T. J.; Todd, A. M. A Research Project in the Organic Instructional Laboratory Involving the Suzuki−Miyaura Cross Coupling Reaction. Chem. Educator 2007, 12, 414−418. (10) Mercer, S. M.; Andraos, J.; Jessop, P. G. Choosing the Greenest Synthesis: A Multivariate Metric Green Chemistry Exercise. J. Chem. Educ. 2012, 89, 215−220. (11) Goodwin, T. E. An Asymptotic Approach to the Development of a Green Organic Chemistry Laboratory. J. Chem. Educ. 2004, 81, 1187−1190.
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uring the past decade, the Nobel Prize-winning Suzuki reaction1 has been heavily used as a vehicle to teach fundamental green chemistry principles.2−9 As examples, through performing a Suzuki coupling, undergraduates have learned about aqueous reactivity,2,5−9 energy-efficient conditions,3 greener reaction solvents,4 and catalyst recycling.8 A recent article in this Journal explored use of microwave heating as a more sustainable technology in the context of a Suzuki biaryl synthesis.2 While this latter methodology is to be applauded, it is worth underscoring that there are many factors impacting the “greenness” of a laboratory process. Mercer et al. have described a multivariate metric exercise requiring students to determine the environmental impact of several organic syntheses.10 In this approach, a reaction workup is considered as carefully as the transformation that precedes it. The microwave-assisted aqueous Suzuki reactions outlined by Soares et al. have problematic workups from a green chemistry perspective, as they involve (i) filtration through Celite; (ii) liquid−liquid extraction using dichloromethane; and (iii) flashcolumn chromatography.2 While these three steps may be necessary to obtain purified products in acceptable yields, instructors have a duty to emphasize the “non-green” aspects of any experiment used in green chemistry teaching, so that improvements might be suggested. This was concisely proposed by Goodwin in the form of three student laboratory report questions:11 • “What was green about the experiment?” • “What was not green?” • “How could the experiment be made greener?”
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AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Notes
The authors declare no competing financial interest.
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REFERENCES
(1) Kauffman, G. B.; Adloff, J.-P. The 2010 Nobel Prize in ChemistryGreat Art in a Test Tube. Chem. Educator 2011, 16, 51−58. (2) Soares, P.; Fernandes, C.; Chavarria, D.; Borges, F. MicrowaveAssisted Synthesis of 5-Phenyl-2-hydroxyacetophenone Derivatives by © XXXX American Chemical Society and Division of Chemical Education, Inc.
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DOI: 10.1021/ed5008712 J. Chem. Educ. XXXX, XXX, XXX−XXX
