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Polymer=Bound Ketenes and Allenes: Preparation and Applications

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Polymer=Bound Ketenes and Allenes: Preparation and Applications Polymer=BoundKetenes and Allenes: Preparation and Applications Adel Rafai Far A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Department of Chemistry University of Toronto O Copyright by Adel Rafai Far (2000) National Library Bibliothèque nationale ofCanada du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellington Street 395. rue Wellington Ottawa ON KIA ON4 Oaawa ON K1A ON4 Canada CaMda The author has granted a non- L'auteur a accordé une Licence non exclusive licence ailowing the exclusive permettant à la National Libmy of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or seii reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/film, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts £iom it Ni la thèse ni des extraits substantiels may be printed or othenvise de celle-ci ne doivent être impkés reproduced without the author's ou autrement reproduits sans son permission. autorisation. Abstract The main scope of the research presented in this thesis is the investigation of the viabilit y of polymer- bound ketenes and allenes, and of their reactions. These studies represent a continuation both of the current developments in polyrner-bound synthesis. and of the recent progresses in cumulene chemisuy. Attempts were made to use 1,3-dioxin4ones as preçursors of polyrner-bound acylketenes. Usùig both insoluble and soluble polymeric supports, three different polymer-bound clioxùiones were prepared. These were thermally converted to the parent ketenes. but attempts to trap these showed that the main products came from competing hydration. This was countered by reversing the procedure, namely by adding the ketene to the support. Soluble poly(ethy1ene glycol) (MPEGOH) of average MW of 5000 g mol-' was reacted with 2.2.6-trimethyl-1.3-dioxin-Cone. an acetylketene precursor, to give a po Iymer- bound acetoacetate. Condensation of this with primary amines under dehydrating conditions gave polymer-bound enamines, These were then treated with the acetyketene precursor again. and gave 4-pyridones, which were Liberated from the support by methano lysis. Using MPEGOH. the Wang min. and a spacer modified Wang resin. stable polymer-bound silyl ketenes were prepared by the reaction of the hydroxy groups on these polyrners with 2.3-bis(trimethylsily1)- 1-3-butadien- 1.4-dione. a persistent and stable bisketene. The soluble polymer-bound silyl ketene was converted to amides via reaction with amines. Folio wing fluorodesilylation. the amides were cleaved from the support either via methanolysis. to give succinimides or mixed ester amides of succinic acid. or via reaction with butylamine to give unsymmeuîal succinamides. The solid supponed silyl ketenes were subjected to the same process, with the exception that hydrolysis was used for the cleavage. to forrn succinamic acids and esters. The Wang rein supported ketene was also converted to its parent esters under catalysis with base. yielding succinic acid mo noesters. after cleavage. Using MPEGOH. polymer-supporied allenecarboxylates and an aiienylketene were prepared. The alienecarboxylates were treated with amines to give enamines and. fo llo wing treatment with acet yiketene and methanolysis, 4-pyridones were O btained fiom these allenes. The sarne enamines were treated with acryloyl imidazole, to give, afier mathano lysis. glactams. The treatment of the aiienylketene with amines. foilowed by the same reac t ion with acryloy1 imidazo le and methano lysis. also gave Glactarns. iii Acknowledgements Carrying on my doctoral studies in Professor Thomas T. TidweIl's group has been a true privilege. Professor Tidweil is an example of what a supenisor should be: patient. enthusiastic. willing to discuss aii the different aspects of chemistry, and open to new avenues to explore. And 1 would like to thank him above aii for letting me carry on this unusual research in the realrn of ketenes. 1 am also indebted to ail the rnembers past and present of the Tidweiî group, pmicularly Anne tte Allen. Mike FenwicL, Hu& Henry-Riyad. Wenwei Huang. Ronghua Liu and Patrick Moore. It was wondehl to be assoçiated with them. Most of this work wouldn't be biblewithout the skiiis of the support staff at the department of Chemistry: Dan Mathers (ANALEST). Aiex Young (Mass Specuometry). Th Burrow (Solution state NMR). Patricia Aroca-Ouektte and Hiltrud Grondey (Solid state NMR). 1 &O would like to thank Professors McCleiland. Kresge. McMillan. Still and Yudin from the University of Toronto and Professor Lemoff frorn York University for useful suggestions. Above aU. 1 owe aU of this to my family. through their help. support and encouragements. None of this would be possible without my father Afram, my mother Leila. my grandmother Violet, Sherry. Dina and DaMd (Au téléphone: -Alors David. qu* est-cc que tu fais de beau? -Rien, -Tu ne fais rien de beau? -Non...). Thank you for this gift. Table of Contents .. Abstract 11 Acknowledgments iv Table of Contents v Abbreviations ix Supports for Combinatoriai Chemistry xii A few defmitions 1 Chapter one: Polymer-bound cumulenes il Reactivity in po lymer-bound synt hesis Polymer-bound carbodiimides IlIJ Polymer-bound diazoaikanes N] Polymer- bound isocyanates and thioisocyanates VI Polymer-bound ketenes VI] Conclusion VIII] Reîèrences Chapter two: Polymer-bound acyl ketenes: Preparation and attempted use a Applications of ketenes to polymer-bound synthesis a) Dehydro halogenation b) Acyl Meldrum's acid c) Diazoketones d) Chromium carbene complexes ïlJ Acyl ketenes from 4H- 1.3-dioxin-4-ones ïïlJ Acyl ketenes bound on a solid support IV] Soluble polymer-supported 1,3-dioxin4one VI Soluble polyrner-bund synthesis of 4-pyridones a) Preparation of 2.6-dimethyl-4-pyridones b) Atternpted use of alternative acyl ketenes VI] Conclusion Va Experimental 1) Preparation of polymer-bound dioxinone 54 2) freparation of polymer-bound dioxinone 58 3) Soluble polymer-supported dioxinone 64 4) Preparation of 2.6-dimethyl pyridones 5) Preparation of 2.2-dimethyl-6-phenyl- 1.3-dioxin-4-one 6) Preparation of 6-alkyl su bstiuted dioxinones via Meldrurn's acid 7 1 7) Preparation of 5-ethyl-6-trifluoromethyl-2.2-dimethyl- 1.3-dioxin- 4-one (79) 75 8) Preparation of 2,2,5.6-tetramethyl- 1.3-dioxin-&one (80) 76 VWReferences 77 Appendix A: Selected 'H-NMR spectra 83 Appendix B: Selected IR spectra Appendix C: CP-MAS '3~-~~~spectrurn for 54 Chapter three: Stable polymer-bund silylated ketenes 97 r] Introduction 97 LI] Preparation and nucleophilic reactions of a soluble polymer bound silyl ketene 99 Uïj Solid-supported silyl ketenes 104 a) Preparation 104 b) Reaction with amines 105 C) Reaction with alcohok 107 N] Conclusion L 11 V] Experimental 112 1) Soluble polymer-bound ketene 113 2) Solid supponed ketenes 122 VT] References 128 Appendix A: selected 'H-NMR spectra 13 1 Appendix B: selected IR spectra 159 Chapter four: Po lymer- bound allenecarboxylates Tj Introduction II] Soluble polymer-bound allenecarboxylates a) Preparation b) Reactions with amines. Preparation of pyridones and Glactarns L67 III] Soluble po lymer- bound stable dieny1 ketene 170 IV] Atternpts towards the preparation of allenes on a solid support 174 V] Conclusion 179 Vu Experimental 180 1) Polymer-bund allei-aarboxylates 181 2) Polyrner-bound alleny1 ketene 191 3) Solid supported reagents L93 Va) References 196 Appendix A: selected 'H-NMR spectra 200 Appendix B: IR spectrum for aiienyl ketene 18 225 Appendk C: NOESY spectrum for l3w 227 Yields and purities Abbreviations - Ac acetyl Bu but y1 calcd calculated cm-' wavenu rn ber (inverse entheters) CF-MAS crosspoiarization-magie angle spinning OC degrees centigrade DMSO dimethy1 sulfoxide d doublet DBU 1,8-diazabicycl0[5.4.0]undec-7-ene DCC dic yclo hexy Icarbodümide dd doublet of doublets DE AD diethyl azodicarboxylate DIC Diisopropy Icarbodiimide DIPEA düsopropylethylamine EIMS electron impact rnass spectrometry (low resolu t ion) Et Ethyl EtOAc Ethyl acetate E gram HMPA hexameth ylphosphoramide HRMS high resolution mass spectrometry hv irradiation Hz hertz 1- iso IR in frared 3 coupling constant m multiplet M rnolarity M+ molecular ion Me methyl PL microliters mg miliigrams mL milliliters mP melting point mm01 millimoles mo 1 moles MS mass spectrome try m/z mas to charge ratio n- normal N normality nm nanometer NMP 1 -Methyl-2-p yrro iidone NMR nuclear magnetic resonance spectroscopy PEG polyethylene glycol Ph meny1 Pr P~OPY~ PS ~01~stvene parts per million quartet singlet f- tertiary TBAF tetrabutylammonium fluoride TEA triethylarnine THF tetrahydrofuran TMEDA N,N,N'.NT-tetramethylethytenediamine TMS trirnethylsilyl UV ultraviolet VPC vapor phase chromatography Supports for Combinatorid Chemistry will be used to represent polystyrene crosslinked with divinylbenzene Wang resin SASRIN resin HAL resin OMe xii Rink amide (X = NHFmoc) or ester (X = OH) resin MBHA resin TentagelTMresins (X is a hnçtionality) xiii xiv A few definitions Ail of this thesis deals with polymer-bound chemistry. It appears therefore usehl to introduce the reader to some of the terminology used. Library: Set of molecules with common structurai elernents. Generally meant for a mixture of the molecules in this set. The broader definition is preferred hem. Deconvolution: Characterization of the moiecules in a library having the desired properties. Combinatorial chemistrv; Field of chemistry dealing with the preparation. characterization, evaluation and deconvo1ution of libraries. Sup~ort:A substance which can bind, generally (but not necessarily) covalently, a number of molecules of another substance. and because of its unusual properties can be easily separated from reaction mixtures. Polvmer-bound or mlvmer-su~~onedrea~ent kom~ound. substance): the product obtained by bonding a nurnber of small molecules to a polymenc support.
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