Organometallic Chemistry of Five-Membered Heterocycles PDF
Preview Organometallic Chemistry of Five-Membered Heterocycles
ORGANOMETALLIC CHEMISTRY OF FIVE-MEMBERED HETEROCYCLES ORGANOMETALLIC CHEMISTRY OF FIVE-MEMBERED HETEROCYCLES A S LEXANDER ADIMENKO ProfessorofChemistry,UniversityofFortHare,Alice,RepublicofSouthAfrica Elsevier Radarweg29,POBox211,1000AEAmsterdam,Netherlands TheBoulevard,LangfordLane,Kidlington,OxfordOX51GB,UnitedKingdom 50HampshireStreet,5thFloor,Cambridge,MA02139,UnitedStates Copyright©2020ElsevierLtd.Allrightsreserved. Nopartofthispublicationmaybereproducedortransmittedinanyformorbyanymeans,electronicormechanical, includingphotocopying,recording,oranyinformationstorageandretrievalsystem,withoutpermissioninwritingfromthe publisher.Detailsonhowtoseekpermission,furtherinformationaboutthePublisher’spermissionspoliciesandour arrangementswithorganizationssuchastheCopyrightClearanceCenterandtheCopyrightLicensingAgency,canbefound atourwebsite:www.elsevier.com/permissions. ThisbookandtheindividualcontributionscontainedinitareprotectedundercopyrightbythePublisher(otherthanasmay benotedherein). Notices Knowledgeandbestpracticeinthisfieldareconstantlychanging.Asnewresearchandexperiencebroadenour understanding,changesinresearchmethods,professionalpractices,ormedicaltreatmentmaybecomenecessary. Practitionersandresearchersmustalwaysrelyontheirownexperienceandknowledgeinevaluatingandusingany information,methods,compounds,orexperimentsdescribedherein.Inusingsuchinformationormethodstheyshouldbe mindfuloftheirownsafetyandthesafetyofothers,includingpartiesforwhomtheyhaveaprofessionalresponsibility. Tothefullestextentofthelaw,neitherthePublishernortheauthors,contributors,oreditors,assumeanyliabilityforany injuryand/ordamagetopersonsorpropertyasamatterofproductsliability,negligenceorotherwise,orfromanyuseor operationofanymethods,products,instructions,orideascontainedinthematerialherein. BritishLibraryCataloguing-in-PublicationData AcataloguerecordforthisbookisavailablefromtheBritishLibrary LibraryofCongressCataloging-in-PublicationData AcatalogrecordforthisbookisavailablefromtheLibraryofCongress ISBN:978-0-08-102860-5 ForInformationonallElsevierpublications visitourwebsiteathttps://www.elsevier.com/books-and-journals Publisher:SusanDennis AcquisitionEditor:EmilyM.McCloskey EditorialProjectManager:EmeraldLi ProductionProjectManager:DivyaKrishnaKumar CoverDesigner:MatthewLimbert TypesetbyMPSLimited,Chennai,India Contents Abbreviations vii Introduction ix 1. Furans and benzannulated forms 1 1.1 Coordinationmodes 1 1.2 Reactivityofcoordinatedfuran 17 1.3 Derivativesoffuran 25 1.4 Conclusion 41 References 41 2. Thiophenes, benzannulated forms, and analogs 47 2.1 Coordinationmodes 48 2.2 Reactivityoftheη5-coordinatedthiophenes 110 2.3 Reactivityoftheη6-coordinatedcomplexes 121 2.4 Reactivityoftheη4-coordinatedcomplexes 126 2.5 Reactivityoftheη2-coordinatedthiophenes 134 2.6 Derivatives 136 2.7 Conclusion 212 References 213 3. Pyrroles and benzannulated forms 239 3.1 Coordinationmodes 239 3.2 Reactivityofthecoordinatedpyrroles 291 3.3 Derivatives 318 3.4 Conclusion 529 References 531 Furtherreading 564 4. Phospholes, benzannulated forms, and analogs 565 4.1 Coordinationmodes 566 4.2 Reactivityofthecoordinatedphospholesandanalogs 620 4.3 Mixedheterocyclescontainingphospholeorphospholylmoiety 674 4.4 Conclusion 679 References 679 v vi CONTENTS 5. Siloles and analogs 691 5.1 Conclusion 707 References 708 6. Boroles and analogs 711 6.1 Conclusion 740 References 740 General conclusion 745 Index 761 Abbreviations [9]aneS3 1,4,7-trithiacyclononane Ac acetyl acac acetylacetonate Ad adamantyl AIBN azobisisobutyronitrile AN acetonitrile Ar aryl Ar0 tetrakis(3,5-bis(trifluoromethyl)phenyl)borate bda benzylideneacetone binap 2,20-bis(diphenylphosphino)-1,10-binaphthyl bpy 2,20-bipyridine Bun n-butyl But tert-butyl cod cycloocatadiene-1,5 COE cyclooctene COT cyclooctatetraene Cp cyclopentadienyl Cp0 variouslysubstitutedcyclopentadienyl Cp* pentamethylcyclopentadienyl Cy cyclohexyl dba dibenzylideneacetone DDQ 2,3-dichloro-5,6-dicyano-1,4-benzoquinone depe 1,2-bis(diethylphosphino)ethane dippe 1,2-bis(diisopropylphosphino)ethane DMAC dimethylacetamide DME dimethoxyethane DMF dimethylformamide dmpe 1,2-bis(dimethylphosphino)ethane dmpm 1,2-bis(dimethylphosphino)methane DMSO dimethylsulfoxide dppe 1,2-bis(diphenylphosphino)ethane dppf 1,2-bis(diphenylphosphino)ferrocene dppm 1,2-bis(diphenylphosphino)methane dppn 1,8-bis(diphenylphosphino)naphthalene dppp 1,3-bis(diphenylphosphino)propane EDA ethylenediamine en ethylenediamine Et ethyl Facac hexafluoroacetylacetonate Fc ferrocenyl HOMO highestoccupiedmolecularorbital Im imidazolate LDA lithiumdisopropylamide LUMO lowestunoccupiedmolecularorbital Me methyl vii viii Abbreviations Mes mesityl Ms methanesulfonyl Naph naphthyl nbd norbornadiene-2,5 Nu nucleophile OLED organiclight-emittingdiode OTf triflate Ph phenyl phen 1,10-phenthroline Pri isopropyl Py pyridine Pz pyrazolate RT roomtemperature solv solvent TCNE tetracyanoethylene TCNQ tetracyanoquinodimethane THF tetrahydrofuran THT tetrahydrothiophene TMEDA tetramethylethylenediamine TMP tetramethylpyrrole TMT tetramethylthiophene Tol tolyl Tp trispyrazolylborate Tp* tris(3,5-dimethyl-1-pyrazolyl)borate tpp tetraphenylporphyrin tpy 2,20;60,2v-terpyridine Vin vinyl Xy xylyl Introduction For the past 20 years, we prepared a chapter series in organometallic chemistry of het- erocycles published in Advances of Heterocyclic Chemistry. This work led to an idea of pre- paring a set of monographs. The subject is of course enormous, and the main purpose for us was an appreciation of the vast number of published works on the electronic structure, geometry, coordination modes, reactivity, wide variety of functional derivatives, and importance in medicine, catalysis, materials chemistry, photochemistry, and numerous other fields. The book set is thus a broad reference work. Chemists at all levels might find it useful to assist them when first entering the field, or when assessing the state of art; researchers in the related fields like medicinal, materials, or catalytic chemistry would also get useful information. The importance and extent of the subject matter continues to grow so that it is one of the largest subdivisions of organometallic chemistry, which has contrib- uted essentially to the progress of diverse fields of science and technology. Therefore the bulk of material cannot be squeezed into one book of reasonable size and may be subdi- vided into thefollowing parts: Organometallic chemistry of five-membered monoheterocycles Organometallic chemistry of azoles Organometallic chemistry of six-memberedmonoheterocycles Organometallic chemistry of azines Applied organometallic chemistry of heterocycles In the current volume organometallic chemistry of five-membered monoheterocycles is in thefocus. Five-membered rings with nitrogen, phosphorus, arsenic, or antimony; and oxygen, sul- fur, selenium, or tellurium have four π-electrons from the two double bonds and two non- bonded π-electrons on the heteroatom, so that the five-membered aromatic heterocycles pyrrole, phosphole, furan, and thiophene are aromatic. They are related to the cyclopenta- dienyl anion by replacement of one CH(cid:1) group with NH, PR, O, or S heteroatoms, each contributing two electrons to the aromatic sextet. Heteroatoms of this type have only sin- gle bonds and are called pyrrole-like. Six electrons are associated with the five ring atoms. The π-excess of these five-membered rings is accompanied by high π-donor character and a diversity of the η5-coordinated organometallic compounds. For five-membered rings with one heteroatom, benzannulation generally stabilizes an aromatic system, for example, carbazole.indole.isoindole.pyrrole. The borole system is isoelectronic to the cyclo- pentadienyl cation and four π-electrons lead to antiaromaticity, which transforms to aro- maticity in organometallic environment. Silole is analogous to cyclopentadiene but reveals the propertiesnot only of adienebut also of a heteroaromatic ligand. Heteroaromatic ligands are subdivided into π-excessive, five-membered rings exempli- fied by pyrrole, furan, and thiophene, and π-deficient six-membered rings, for example, ix x Introduction pyridine. The π-excessive heterocycles are extremely reactive toward electrophilic attack and, with the exception of thiophene, do not exhibit the chemical inertness associated with aromatic benzene derivatives. Conversely, the π-deficient heterocycles are inert with respect to electrophilic attack. The reactivity of the five-membered heterocycles pyrrole, furan, thiophene, and imidaz- ole is characterized by interactions with electrophilic reagents. The precise nature of these reactions depends on the particular ring system. Thiophenes undergo facile electrophilic substitution, whereas the other compounds exhibit a range of polymerization and other Lewis acid-initiated reactions upon treatment with electrophiles. Organometallic com- pounds of five-membered heterocyclic ligands have their own features of reactivity, enhancing their synthetic potential. Typical derivatives of five-membered heterocycles include those with O(cid:1) (S(cid:1), Se(cid:1)) functional groups, amines, aminomethyls, various Schiff bases, and phosphines. For pyr- roles there is a tendency to form dipyrro-, tripyrro-, and macrocyclic compounds of vari- ous types. Porphyrins and phthalocyanines are a subject of separate discussion, although organometallic compounds of such macrocyclic ligands are exceptionally scarce. Dipyrrins are regarded as half-porphyrins. N-Confused porphyrins have at least one inverted pyr- role subunit. Carbaporphyrinoids contain carbocyclic rings instead of the pyrrole rings and include oxybenzi-, carba-, tropi-, and azuliporphyrins. Porphyrinoids (including car- baporphyrinoids) are macrocycles suitable for studying organometallic chemistry in a con- fined environment. The CH or CC bonds are very close to the metal ion and lead to a unique coordination geometry and reactivity. Thus the internal carbon can be modified by alkylation, halogenation, nitration, acetoxylation, C-cyanide addition, oxygen or sulfur insertion, formation of ketal, pyridination, amination, or phosphinylation. Triphyrins con- tain three pyrrole rings linked through meso-sp2 carbon atoms. Carbaporphyrins have one or more carbon atoms in place of nitrogen ring atoms including the porphyrin and phtha- locyanineisomers:N-confusedporphyrin andbenziphthalocyaninewhereoneoftheisoin- doline rings is replaced with a benzene ring. Organometallic compounds are remarkable especially dueto the stabilization of unusualmetal oxidation states. References are designated by a number-letter coding of which the first numbers record the year of publication, the next one to four letters denote the journal, and the final num- bers give the page. A list of journal codes is given in alphabetical order. For journals that are published in separate parts, the part letter or number is given (when necessary) in parentheses immediately after the journal code letters. Journal volume numbers are not included in the code numbers unless more than one volume was published in the year in question, in which case the volume number is included in parentheses immediately after the journal code letters. The author will always remember Professor Alan Roy Katritzky who edited my numerous chapters in Advances of Heterocyclic Chemistry and inspired me to start working on the monograph series, Professor Alexander Dmitrievich Garnovskii in appreciation of our long-standing collaboration resulting in mutually complementary papers, books, and chapters in the books, Professor Pavel Aleksandrovich Sadimenko for his lessons in dedi- cated and hard work style. Professor Vladimir Isaakovich Minkin is my main chemistry teacher and he stimulated me for writing and many ideas have arisen from communica- tion with him.
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