Cross dehydrogenative coupling

Cross dehydrogenative coupling (also known as CDC reaction), coined by Chao-Jun Li of McGill University,{{Cite journal|last=Li|first=Chao-Jun|date=2009-02-17|title=Cross-Dehydrogenative Coupling (CDC): Exploring C−C Bond Formations beyond Functional Group Transformations|url=https://pubs.acs.org/doi/10.1021/ar800164n|journal=Accounts of Chemical Research|language=en|volume=42|issue=2|pages=335–344|doi=10.1021/ar800164n|pmid=19220064|issn=0001-4842|url-access=subscription}}{{Cite journal|last1=Li|first1=Z.|last2=Bohle|first2=D. S.|last3=Li|first3=C.-J.|date=2006-06-13|title=Cu-catalyzed cross-dehydrogenative coupling: A versatile strategy for C-C bond formations via the oxidative activation of sp3 C-H bonds|journal=Proceedings of the National Academy of Sciences|language=en|volume=103|issue=24|pages=8928–8933|doi=10.1073/pnas.0601687103|issn=0027-8424|pmc=1482542|pmid=16754869|bibcode=2006PNAS..103.8928L|doi-access=free }}{{Cite web|date=2016-12-17|title=Cross-Dehydrogenative Coupling|url=https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Modules_and_Websites_(Inorganic_Chemistry)/Catalysis/Catalyst_Examples/Cross-Dehydrogenative_Coupling|access-date=2020-10-22|website=Chemistry LibreTexts|language=en}}{{Cite book|date=2014|editor-last=Li|editor-first=Chao-Jun|title=From C-H to C-C Bonds|url=https://doi-org.proxy3.library.mcgill.ca/10.1039/9781782620082|series=Green Chemistry Series|doi=10.1039/9781782620082|isbn=978-1-84973-797-5|issn=1757-7047}} is a type of coupling reaction allowing the construction of a carbon–carbon bond{{Cite journal|last1=Yeung|first1=Charles S.|last2=Dong|first2=Vy M.|date=2011-03-09|title=Catalytic Dehydrogenative Cross-Coupling: Forming Carbon−Carbon Bonds by Oxidizing Two Carbon−Hydrogen Bonds|url=https://doi-org.proxy3.library.mcgill.ca/10.1021/cr100280d|journal=Chemical Reviews|volume=111|issue=3|pages=1215–1292|doi=10.1021/cr100280d|pmid=21391561|issn=0009-2665|url-access=subscription}} or C-Heteroatom bond{{Cite journal|last1=Krylov|first1=Igor B.|last2=Vil’|first2=Vera A.|last3=Terent’ev|first3=Alexander O.|date=2015-01-20|title=Cross-dehydrogenative coupling for the intermolecular C–O bond formation|url=https://www.beilstein-journals.org/bjoc/articles/11/13|journal=Beilstein Journal of Organic Chemistry|language=en|volume=11|issue=1|pages=92–146|doi=10.3762/bjoc.11.13|issn=1860-5397|pmc=4311763|pmid=25670997}} directly from C–H bonds in the presence of an oxidant, leading to the thermodynamically unfavorable formal removal of a H₂ molecule. As such, CDC are couplings belonging to the C–H activation strategy.

File:Cross-Dehydrogenative-Coupling.png

The key to the CDC coupling is eliminating the need for substrate prefunctionalization. Therefore, the CDC reaction has the advantages of high efficiency, Atom economy and environmental friendliness. Such reactions can be achieved or activated by transition-metal catalysis or oxidation reaction (e.g. benzoquinone, peroxides, O₂, hypervalent iodine), or by either photocatalysis or electrocatalysis. The mechanism and reactivity of the CDC reactions varies dramatically depending on the substrate.{{Citation|last1=Tsang|first1=Althea S.-K.|title=CHAPTER 11. Mechanisms of Cross-Dehydrogenative-Coupling Reactions|date=2014|url=http://ebook.rsc.org/?DOI=10.1039/9781782620082-00254|series=Green Chemistry Series|pages=254–294|editor-last=Li|editor-first=Chao-Jun|place=Cambridge|publisher=Royal Society of Chemistry|doi=10.1039/9781782620082-00254|isbn=978-1-84973-797-5|access-date=2020-10-22|last2=Park|first2=Soo J.|last3=Todd|first3=Matthew H.|url-access=subscription}}{{Cite journal|last1=Huang|first1=Chia-Yu|last2=Kang|first2=Hyotaik|last3=Li|first3=Jianbin|last4=Li|first4=Chao-Jun|date=2019-10-18|title=En Route to Intermolecular Cross-Dehydrogenative Coupling Reactions|url=https://pubs.acs.org/doi/10.1021/acs.joc.9b01704|journal=The Journal of Organic Chemistry|language=en|volume=84|issue=20|pages=12705–12721|doi=10.1021/acs.joc.9b01704|pmid=31441304|s2cid=201617266 |issn=0022-3263|url-access=subscription}} CDC reactions have been used to construct bonds between sp³-sp³, sp³-sp², sp³-sp, sp²-sp², sp²-sp and sp-sp C-H bonds.{{Cite journal|last1=Girard|first1=Simon A.|last2=Knauber|first2=Thomas|last3=Li|first3=Chao-Jun|date=2014-01-03|title=The Cross-Dehydrogenative Coupling of C sp 3H Bonds: A Versatile Strategy for CC Bond Formations|url=http://doi.wiley.com/10.1002/anie.201304268|journal=Angewandte Chemie International Edition|language=en|volume=53|issue=1|pages=74–100|doi=10.1002/anie.201304268|pmid=24214829|url-access=subscription}}{{Cite journal|last=Scheuermann|first=Caroline J.|date=2010-03-01|title=Beyond Traditional Cross Couplings: The Scope of the Cross Dehydrogenative Coupling Reaction|journal=Chemistry: An Asian Journal|language=en|volume=5|issue=3|pages=436–451|doi=10.1002/asia.200900487|pmid=20041458|doi-access=free}} The synthesis and functionalization of various nitrogen, oxygen and sulfur-containing heterocycles have also been achieved via CDC.{{Cite book|url=http://link.springer.com/10.1007/978-981-13-9144-6|title=Heterocycles via Cross Dehydrogenative Coupling: Synthesis and Functionalization|date=2019|publisher=Springer Singapore|isbn=978-981-13-9143-9|editor-last=Srivastava|editor-first=Ananya|location=Singapore|language=en|doi=10.1007/978-981-13-9144-6|s2cid=201623590|editor-last2=Jana|editor-first2=Chandan K.}}