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Directing group
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<h2 id="transient-directing-groups">Transient directing groups</h2> <p>Since directing groups are ligands, their effectiveness correlates with their affinities for metals. Common functional groups such as ketones usually are only weak ligands and thus often are poor DGs. This problem is solved by the use of a transient directing group. Transient DGs reversibly convert weak DGs (e.g., ketones) into strong DG's (e.g., imines) via a <a href="/facts/Schiff_base/yg29UMLe">Schiff base</a> condensation. Subsequent to serving their role as DGs, the imine can hydrolyze, regenerating the ketone and amine.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> </p> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Sambiagio, C.; D. Schönbauer; R. Blieck; T. Dao-Huy; G. Pototschnig; P. Schaaf; T. Wiesinger; M. F. Zia; J. Wencel-Delord; T. Besset; B. U. W. Maes; M. Schnürch (2018). "A Comprehensive Overview of Directing Groups Applied in Metal-Catalysed C–H functionalisation chemistry". Chem. Soc. Rev. 47 (17): 6603–6743. doi:10.1039/C8CS00201K. PMC 6113863. PMID 30033454. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6113863" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6113863</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Sambiagio, C.; D. Schönbauer; R. Blieck; T. Dao-Huy; G. Pototschnig; P. Schaaf; T. Wiesinger; M. F. Zia; J. Wencel-Delord; T. Besset; B. U. W. Maes; M. Schnürch (2018). "A Comprehensive Overview of Directing Groups Applied in Metal-Catalysed C–H functionalisation chemistry". Chem. Soc. Rev. 47 (17): 6603–6743. doi:10.1039/C8CS00201K. PMC 6113863. PMID 30033454. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6113863" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6113863</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Snieckus, Victor (1990). "Directed ortho metalation. Tertiary amide and O-carbamate directors in synthetic strategies for polysubstituted aromatics" Chem. Rev.; 90 (6): 879–933. <a href="https://pubs.acs.org/doi/pdf/10.1021/cr00104a001" target="_blank">https://pubs.acs.org/doi/pdf/10.1021/cr00104a001</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>He, Jian; Wasa, Masayuki; Chan, Kelvin S. L.; Shao, Qian; Yu, Jin-Quan (2017). "Palladium-Catalyzed Transformations of Alkyl C–H Bonds". Chemical Reviews. 117 (13): 8754–8786. doi:10.1021/acs.chemrev.6b00622. PMC 5516964. PMID 28697604. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5516964" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5516964</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>St John-Campbell, S.; J. A. Bull (2018). "Transient imines as 'next generation' directing groups for the catalytic functionalisation of C–H bonds in a single operation" (PDF). Organic & Biomolecular Chemistry. 16 (25): 4582–4595. doi:10.1039/C8OB00926K. hdl:10044/1/60231. PMID 29796566. <a href="http://spiral.imperial.ac.uk/bitstream/10044/1/60231/2/MS%20transient%20review%20OBC%20revised.pdf" target="_blank">http://spiral.imperial.ac.uk/bitstream/10044/1/60231/2/MS%20transient%20review%20OBC%20revised.pdf</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> </ol>