Oxidation of primary alcohols to carboxylic acids : a guide to current common practice PDF
Preview Oxidation of primary alcohols to carboxylic acids : a guide to current common practice
Oxidation of Primary Alcohols to Carboxylic Acids BASIC REACTIONS IN ORGANIC SYNTHESIS EDITOR-IN-CHIEF:GABRIELTOJO DEPARTMENTOFORGANICCHEMISTRY FACULTYOFCHEMISTRY UNIVERSITYOFSANTIAGODECOMPOSTELA 15872-SANTIAGODECOMPOSTELASPAIN [email protected] OxidationofAlcoholstoAldehydesandKetones: AGuidetoCurrentCommonPractice,byGabrielTojoandMarcosFernández OxidationofPrimaryAlcoholstoCarboxylicAcids: AGuidetoCurrentCommonPractice,byGabrielTojoandMarcosFernández Oxidation of Primary Alcohols to Carboxylic Acids A Guide to Current Common Practice GABRIEL TOJO and MARCOS FERNÁNDEZ Authors: GabrielTojo MarcosFernández DepartmentofOrganicChemistry DepartmentofOrganicChemistry FacultyofChemistry FacultyofChemistry UniversityofSantiagodeCompostela UniversityofSantiagodeCompostela 15872-SantiagodeCompostela 15872-SantiagodeCompostela Spain Spain Editor-in-Chief GabrielTojo DepartmentofOrganicChemistry FacultyofChemistry UniversityofSantiagodeCompostela 15872-SantiagodeCompostela Spain LibraryofCongressControlNumber:2006929452 ISBN-10:0-387-35431-X ISBN-13:978-0387-35431-6 e-ISBN-10:0-387-35432-8 e-ISBN-13:978-0387-35432-3 Printedonacid-freepaper. ©2007SpringerScience+BusinessMedia,LLC Allrightsreserved.Thisworkmaynotbetranslatedorcopiedinwholeorinpartwithoutthewritten permissionofthepublisher(SpringerScience+BusinessMedia,LLC,233SpringStreet,NewYork, NY10013,USA),exceptforbriefexcerptsinconnectionwithreviewsorscholarlyanalysis.Usein connection with any form of information storage and retrieval, electronic adaptation, computer software,orbysimilarordissimilarmethodologynowknownorhereafterdevelopedisforbidden. The use in this publication of trade names, trademarks, service marks and similar terms, even if theyarenotidentifiedassuch,isnottobetakenasanexpressionofopinionastowhetherornot theyaresubjecttoproprietaryrights. 10987654321 springer.com This book is dedicated to the thousands of scientists cited in the references who constructed our present knowledge on the oxidation of primary alcohols to carboxylic acids. Thanks to their collective effort, the preparation of medicines, pesticides, colorants, and a variety of chemicals that make life more enjoyable, is greatly facilitated. Preface to the Series Thereisnaturalselectioninthesyntheticorganiclaboratory.Successfulreagents findtheirwayintospecializedjournalsandtendtopopulateresearchers’benches. Sometimes, old species—like active manganese dioxide in the oxidation of unsaturated alcohols—are so well adapted to a certain reaction niche that they remain unchallenged for a long time. On other occasions, a successful new species—likeDessMartinperiodinane—enjoysapopulationexplosionandvery quicklyinhabitsagreatnumberoflaboratories.Ontheotherhand,theliterature isfilledwithpromisingnewreagentsthatfellintooblivionbecausenobodywas able to replicate the initial results on more challenging substrates. Thisseries,whichconsistsofacollectionofmonographsonbasicreactions in organic synthesis, is not primarily aimed at specialized researchers interested in the development of new reagents. Rather, it is written with the objective of beingapracticalguideforanykindofscientist,beitachemistofwhateversort, a pharmacologist, a biochemist, or whoever has the practical need to perform a certainbasicsyntheticoperationinthequickestandmostreliableway.Therefore, great emphasis is given to those reagents that are employed most often in laboratories,becausetheirubiquityprovesthattheypossessagreaterreliability. Reagentsappearinginonlyafewpublications,regardlessofpromisingpotential, are only briefly mentioned. We prefer to err on the side of ignoring some good reagents, rather than including bad reagents that would lead researchers to lose precious time. Thebooksfromthisseriesaremeanttobeplacednearworkingbenchesin laboratories,ratherthanontheshelvesoflibraries.Thatiswhyfullexperimental details for important reactions are provided. Although many of references from the literature are facilitated, this series is written with the aim of avoiding as muchaspossibletheneedtoconsultoriginalresearcharticles.Manyresearchers do not have scientific libraries possessing numerous chemical journals readily available, and, many times, although such libraries might be on hand, it is inconvenient to leave the laboratory in order to consult some reference. Our aim is to facilitate practical help for anybody preparing new organic compounds. vii Preface There is a common view among organic chemists that simple functional group transformations are a mature technology away from the forefront in the Art of Organic Synthesis. This is undoubtedly not the case in the conversion of primaryalcoholsintocarboxylicacids.Anidealreagentforsuchtransformation should be (1) reliable and efficient with regard to all molecules, including complex structures possessing oxidation-sensitive functional groups, (2) cheap, and (3) environmentally friendly. There is no such reagent, even if we limit ourselvestothemoremundaneneedofanythingabletoprovideacertainmuch- needed carboxylic acid, regardless of price and ecology. This state of affairs is highlighted by the fact that in forty percent of cases the oxidation of primary alcoholstoacidsisperformedusingatwo-stepprocedureviathecorresponding aldehydes;somethingthatprovesthattheoxidationofalcoholstoaldehydesisa muchmorematuretechnologythantheoxidationofalcoholstocarboxylicacids. This monograph is a laboratory guide for the transformation of primary alcohols into carboxylic acids. It displays a panorama of the state of the art for this functional group transformation, highlighting the weaponry currently availableforscientistsandareaswherefurtherprogressisneeded.Inconformity with the rest of the series, a selection is made to include those procedures that have proved more reliable in many laboratories around the globe. ix Abbreviations Ac acetyl Me methyl Alloc allyloxycarbonyl MEM (2-methoxyethoxy)methyl BAIB bis(acetoxy)iodobenzene min. minute Bn benzyl MOM methoxymethyl Boc t-butoxycarbonyl MS molecular sieves b.p. boiling point MTBE methyl t-butyl ether Bu n-butyl MW molecular weight t-Bu tert-butyl NCS N-chlorosuccinimide Bz benzoyl NMO N-methylmorpholine ca. circa N-oxide CA Chemical Abstracts NMR nuclear magnetic cat. catalytic resonance Cbz benzyloxycarbonyl PCC pyridinium DCAA dichloroacetic acid chlorochromate DCC N(cid:2)N(cid:2)-dicyclohexyl PDC pyridinium dichromate carbodiimide Ph phenyl DMF dimethylformamide PhF 9-phenylfluorenyl DMP Dess-Martin periodinane Pht phthaloyl DMSO dimethyl sulfoxide PMB p-methoxybenzyl ee enantiomeric excess ppm parts per million EE 1-ethoxyethyl Pr propyl eq. equivalent Py pyridine Et ethyl ref. reflux Fmoc 9-fluorenyl r.t. room temperature methoxycarbonyl sat. saturated g gram T temperature h hour TBDPS t-butyldiphenylsilyl i-Pr isopropyl TBS t-butyldimethylsilyl L liter TEMPO 2,2,6,6-tetramethyl- m multiplet 1-piperidinyloxy free M mol/L radical MCPBA m-chloroperoxybenzoic TFA trifluoroacetic acid acid TFAA trifluoroacetic anhydride xi xii Abbreviations THF tetrahydrofuran TPAP tetrapropylammonium THP tetrahydropyran-2-yl perruthenate T internal temperature v volume i TIPS triisopropylsilyl w weight TMS trimethylsilyl Z benzyloxycarbonyl Contents 1. Permanganate..................................................... 1 1.1.Introduction.................................................... 1 1.2.General Procedure for Oxidation of Primary Alcohols to Carboxylic Acids with Potassium Permanganate ............................. 5 1.3.Functional Group and Protecting Group Sensitivity to Potassium Permanganate.................................................. 7 1.4.Side Reactions................................................. 9 1.5.References..................................................... 10 2. Jones and Other CrO -Based Oxidations........................... 13 3 2.1.Introduction.................................................... 13 Mechanism..................................................... 13 Inverse Addition................................................ 15 Solvent........................................................ 16 Acidity........................................................ 17 Zhao’s Catalytic CrO Oxidation................................. 18 3 2.2.General Procedure for Oxidation of Primary Alcohols to Carboxylic Acids with Jones Reagent.......................... 19 2.3.Functional Group and Protecting Group Sensitivity to Jones Oxidation...................................................... 21 2.4.Side Reactions................................................. 25 2.5.References..................................................... 28 3. Pyridinium Dichromate (PDC) in Dimethylformamide. The Method of Corey and Schmidt................................. 33 3.1.Introduction.................................................... 33 3.2.General Procedure for Oxidation of Aliphatic Primary Alcohols to Carboxylic Acids with Pyridinium Dichromate in Dimethylformamide. Method of Corey and Schmidt............. 34 3.3.Functional Group and Protecting Group Sensitivity to PDC in DMF 36 3.4.Side Reactions................................................. 38 3.5.References..................................................... 39 xiii
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