Cobalt carbonyl ionic liquids based on the 1,1,3,3-tetra-alkylguanidine cation: Novel, highly efficient, and reusable catalysts for the carbonylation of epoxides

Article abstract of DOI:10.1016/S1872-2067(17)62824-9

A series of novel cobalt carbonyl ionic liquids based on 1,1,3,3-tetra-alkyl-guanidine, such as [1,1-dimethyl-3,3-diethylguanidinium][Co(CO)₄] (3a), [1,1-dimethyl-3,3-dibutylguanidinium][Co(CO)₄] (3b), [1,1-dimethyl-3,3-tetramethyleneguanidinium][Co(CO)₄] (3c), and [1,1-dimethyl-3,3-pentamethyleneguanidinium] [Co(CO)₄] (3d), were synthesized in good yields and were also characterized using infrared spectroscopy, ultraviolet-visible spectroscopy, ¹H nuclear magnetic resonance (NMR) spectroscopy, ¹³C NMR spectroscopy, high–resolution mass spectrometry, differential scanning calorimetry, and thermogravimetric analysis. The four compounds exhibited high thermal and chemical stability. In addition, the catalytic performance of these compounds was investigated in the carbonylation of epoxides, with 3a exhibiting the best catalytic activity without the aid of a base as the additive. The catalyst could be reused at least six times without significant decreases of the selectivity or conversion rate. Moreover, the catalyst system exhibited good tolerance with terminal epoxides bearing alkyl, alkenyl, aryl, alkoxy, and chloromethyl functional groups.

Full text of DOI:10.1016/S1872-2067(17)62824-9

ChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ805–812
ꢀ
ꢀ ꢀ ꢀ
ꢀ ꢀ ꢀ ꢀ
a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m
ꢀ
j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c h n j c
ꢀ
ꢀ
Article
Cobaltꢀcarbonylꢀionicꢀliquidsꢀbasedꢀonꢀtheꢀ
,1,3,3‐tetra‐alkylguanidineꢀcation:ꢀNovel,ꢀhighlyꢀefficient,ꢀandꢀ ꢀ
reusableꢀcatalystsꢀforꢀtheꢀcarbonylationꢀofꢀepoxidesꢀ
1
a,b
a
a
a
a,
WeiꢀZhangꢀ ,ꢀFengꢀHanꢀ ,ꢀJinꢀTongꢀ ,ꢀChunguꢀXiaꢀ ,ꢀJianhuaꢀLiuꢀ *
ꢀ
aꢀStateꢀKeyꢀLaboratoryꢀforꢀOxoꢀSynthesisꢀandꢀSelectiveꢀOxidation,ꢀLanzhouꢀInstituteꢀofꢀChemicalꢀPhysics,ꢀChineseꢀAcademyꢀofꢀSciences,ꢀLanzhouꢀ730000,ꢀ
Gansu,ꢀChinaꢀ
bꢀUniversityꢀofꢀChineseꢀAcademyꢀofꢀSciences,ꢀBeijingꢀ100049,ꢀChinaꢀ
A R T I C L E ꢀ I N F O ꢀ
A B S T R A C T ꢀ
Articleꢀhistory:ꢀ
Aꢀ seriesꢀ ofꢀ novelꢀ cobaltꢀ carbonylꢀ ionicꢀ liquidsꢀ basedꢀ onꢀ 1,1,3,3‐tetra‐alkyl‐guanidine,ꢀ suchꢀ asꢀ
Receivedꢀ26ꢀJanuaryꢀ2017ꢀ
Acceptedꢀ23ꢀMarchꢀ2017ꢀ
Publishedꢀ5ꢀMayꢀ2017ꢀ
[1,1‐dimethyl‐3,3‐diethylguanidinium][Co(CO)
[Co(CO) ]ꢀ (3b),ꢀ [1,1‐dimethyl‐3,3‐tetramethyleneguanidinium][Co(CO)
thyl‐3,3‐pentamethyleneguanidinium]ꢀ [Co(CO)
4
]ꢀ (3a),ꢀ [1,1‐dimethyl‐3,3‐
ꢀ
dibutylguanidinium]
4
4
]ꢀ (3c),ꢀ andꢀ [1,1‐
ꢀ
dime‐
4
]ꢀ (3d),ꢀ wereꢀ synthesizedꢀ inꢀ goodꢀ yieldsꢀ andꢀ wereꢀ
1
alsoꢀcharacterizedꢀusingꢀinfraredꢀspectroscopy,ꢀultraviolet‐visibleꢀspectroscopy,ꢀ Hꢀnuclearꢀmagnet‐
icꢀresonanceꢀ(NMR)ꢀspectroscopy,ꢀ13CꢀNMRꢀspectroscopy,ꢀhigh‐resolutionꢀmassꢀspectrometry,ꢀdif‐
ferentialꢀscanningꢀcalorimetry,ꢀandꢀthermogravimetricꢀanalysis.ꢀTheꢀfourꢀcompoundsꢀexhibitedꢀhighꢀ
thermalꢀandꢀchemicalꢀstability.ꢀInꢀaddition,ꢀtheꢀcatalyticꢀperformanceꢀofꢀtheseꢀcompoundsꢀwasꢀin‐
vestigatedꢀinꢀtheꢀcarbonylationꢀofꢀepoxides,ꢀwithꢀ3aꢀexhibitingꢀtheꢀbestꢀcatalyticꢀactivityꢀwithoutꢀtheꢀ
aidꢀofꢀaꢀbaseꢀasꢀtheꢀadditive.ꢀTheꢀcatalystꢀcouldꢀbeꢀreusedꢀatꢀleastꢀsixꢀtimesꢀwithoutꢀsignificantꢀde‐
creasesꢀofꢀtheꢀselectivityꢀorꢀconversionꢀrate.ꢀMoreover,ꢀtheꢀcatalystꢀsystemꢀexhibitedꢀgoodꢀtoleranceꢀ
withꢀterminalꢀepoxidesꢀbearingꢀalkyl,ꢀalkenyl,ꢀaryl,ꢀalkoxy,ꢀandꢀchloromethylꢀfunctionalꢀgroups.ꢀ
Keywords:ꢀ
Cobaltꢀcarbonylꢀionicꢀliquidꢀ
Carbonylationꢀ
Epoxideꢀ
Tetra‐alkylguanidineꢀ
Recyclability
©ꢀ2017,ꢀDalianꢀInstituteꢀofꢀChemicalꢀPhysics,ꢀChineseꢀAcademyꢀofꢀSciences.
PublishedꢀbyꢀElsevierꢀB.V.ꢀAllꢀrightsꢀreserved.
1.ꢀ ꢀ Introductionꢀ
catalyticꢀ activeꢀ speciesꢀ hasꢀ beenꢀ usedꢀ inꢀ organometallicꢀ ILsꢀ
[
11,15–21].ꢀ Forꢀ example,ꢀ theꢀ compoundsꢀ [bmim][Co(CO)
(bmimꢀ =ꢀ 1‐butyl‐3‐methylimidazolium),ꢀ [CnPy][Co(CO)
(CnPyꢀ =ꢀ N‐C 2n+1pyridinium),ꢀ [methylguanidinium][Co(CO)
andꢀ [tetramethylguanidinium][Co(CO) ]ꢀ haveꢀ beenꢀ investigat‐
edꢀ byꢀ researchersꢀ [11,22–26].ꢀ Accordingꢀ toꢀ theꢀ previousꢀ re‐
ports,ꢀ [CnPy][Co(CO) ]ꢀ andꢀ [bmim][Co(CO) ]ꢀ organometallicꢀ
4
]ꢀ
Ionicꢀliquidsꢀ(ILs),ꢀsuchꢀasꢀorganicꢀsaltsꢀconsistingꢀofꢀanꢀor‐
4
]ꢀ
ganicꢀcationꢀandꢀanꢀinorganicꢀorꢀorganicꢀanion,ꢀhaveꢀattractedꢀ
considerableꢀattentionꢀbecauseꢀofꢀtheirꢀuniqueꢀproperties,ꢀsuchꢀ
asꢀ negligibleꢀ vaporꢀ pressureꢀ andꢀ highꢀ thermal,ꢀ chemical,ꢀ andꢀ
electrochemicalꢀ stabilityꢀ [1–6].ꢀ Inꢀ addition,ꢀ theꢀ structureꢀ andꢀ
propertiesꢀofꢀILsꢀcanꢀbeꢀmodifiedꢀbyꢀvaryingꢀtheꢀnatureꢀofꢀtheꢀ
anionsꢀandꢀcationsꢀ[7].ꢀRecently,ꢀamongꢀtheꢀvastꢀresearchꢀre‐
latedꢀtoꢀILs,ꢀorganometallicꢀILsꢀ[8–12]ꢀbasedꢀonꢀtransitionꢀmet‐
alsꢀ haveꢀ receivedꢀ increasingꢀ attention,ꢀ especiallyꢀ inꢀ catalysisꢀ
n
H
4
]ꢀ
4
4
4
ILsꢀhaveꢀbeenꢀappliedꢀinꢀtheꢀcarbonylationꢀofꢀepoxides.ꢀHow‐
ever,ꢀtheꢀstabilityꢀandꢀreusabilityꢀofꢀthisꢀtypeꢀofꢀcatalystꢀcouldꢀ
beꢀfurtherꢀenhanced.ꢀ ꢀ
Guanidiniumꢀoffersꢀmanyꢀsignificantꢀandꢀadvantageousꢀfea‐
turesꢀbecauseꢀofꢀitsꢀstructuralꢀcharacteristics.ꢀTheꢀguanidiniumꢀ
cationꢀcanꢀactꢀasꢀaꢀhydrogenꢀbondꢀdonorꢀbecauseꢀofꢀtheꢀpres‐
[
5,13],ꢀbecauseꢀofꢀtheirꢀpotentialꢀcatalyticꢀactivityꢀandꢀconsid‐

erableꢀreusabilityꢀ[11,14].ꢀNotably,ꢀCo(CO)
4
ꢀasꢀaꢀwidelyꢀusedꢀ
*ꢀCorrespondingꢀauthor.ꢀTel:ꢀ+86‐931‐4968286;ꢀFax:ꢀ+86‐931‐8277088;ꢀE‐mail:ꢀjhliu@licp.cas.cnꢀ
ThisꢀworkꢀwasꢀsupportedꢀbyꢀtheꢀNationalꢀNaturalꢀScienceꢀFoundationꢀofꢀChinaꢀ(21373248,ꢀ21673260,ꢀ21133011).ꢀ
DOI:ꢀ10.1016/S1872‐2067(17)62824‐9ꢀ|ꢀhttp://www.sciencedirect.com/science/journal/18722067ꢀ|ꢀChin.ꢀJ.ꢀCatal.,ꢀVol.ꢀ38,ꢀNo.ꢀ5,ꢀMayꢀ2017ꢀ ꢀ ꢀ

806ꢀ
WeiꢀZhangꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ805–812ꢀ
1
13
enceꢀ ofꢀ substitutedꢀ hydrogenꢀ ofꢀ theꢀ Nꢀ atomꢀ andꢀN‐alkylꢀ sub‐
ver,ꢀtheꢀstructuresꢀofꢀtheꢀproductsꢀwereꢀconfirmedꢀbyꢀ H/ Cꢀ
NMR.ꢀ

stituents,ꢀwhichꢀcanꢀsomehowꢀstabilizeꢀtheꢀCo(CO)
4
ꢀanionꢀandꢀ
activateꢀanꢀepoxideꢀ[22,28].ꢀMoreover,ꢀtheꢀguanidiniumꢀcation‐
icꢀ planeꢀ structureꢀ canꢀ beꢀ modifiedꢀ byꢀ theꢀ actionꢀ ofꢀ relativelyꢀ
largeꢀalkylꢀsubstituents.ꢀTherefore,ꢀtheꢀCꢀatomꢀconnectedꢀwithꢀ
theꢀ threeꢀ Nꢀ atomsꢀ presentsꢀ anꢀ electron‐deficientꢀ state.ꢀ Thus,ꢀ
theꢀcationicꢀpartꢀcanꢀbeꢀregardedꢀasꢀaꢀLewisꢀacidꢀ[29],ꢀwhichꢀ
canꢀassistꢀtheꢀring‐openingꢀprocessꢀofꢀtheꢀepoxidesꢀ[23,30–32].ꢀ
Compoundꢀ2ꢀwasꢀpreparedꢀviaꢀneutralizationꢀofꢀ1,1,3,3‐tet‐
ꢀ
ra‐alkylguanidineꢀ withꢀ acids.ꢀ Inꢀ theꢀ experiment,ꢀ 10.0ꢀ mLꢀ ofꢀ
ethanolꢀ andꢀ 1,1,3,3‐tetra‐alkylguanidineꢀ (10.0ꢀ mmol)ꢀ wereꢀ
loadedꢀintoꢀaꢀ100‐mLꢀflaskꢀinꢀanꢀiceꢀwaterꢀbathꢀatꢀ0ꢀ°C.ꢀThen,ꢀ
16.0ꢀmmolꢀofꢀHClꢀinꢀ8.0ꢀmLꢀofꢀethanolꢀwasꢀslowlyꢀaddedꢀintoꢀ
theꢀflaskꢀunderꢀstirring,ꢀandꢀtheꢀstirringꢀwasꢀcontinuedꢀforꢀ4ꢀh.ꢀ
Theꢀreactionꢀmixtureꢀwasꢀevaporatedꢀunderꢀreducedꢀpressure.ꢀ
Theꢀconcentratedꢀmixtureꢀwasꢀthenꢀwashedꢀwithꢀether,ꢀandꢀtheꢀ
productꢀ wasꢀ driedꢀ underꢀ vacuumꢀ atꢀ 50ꢀ °Cꢀ forꢀ 24ꢀ h.ꢀ Allꢀ theꢀ
productsꢀwereꢀwhiteꢀsolids,ꢀexceptꢀforꢀ2b,ꢀwhichꢀwasꢀaꢀcolor‐
Itꢀisꢀ expectedꢀthatꢀ cobaltꢀcarbonylꢀILsꢀ basedꢀ onꢀ1,1,3,3‐tetra‐
ꢀ

alkylguanidineꢀ canꢀ playꢀ theꢀ dualꢀ roleꢀ ofꢀ stabilizingꢀ Co(CO)
4
ꢀ
anionsꢀandꢀactivatingꢀepoxyꢀcompounds.ꢀ
Toꢀ verifyꢀ ourꢀ speculation,ꢀ weꢀ designedꢀ andꢀ synthesizedꢀ aꢀ
seriesꢀofꢀcobaltꢀcarbonylꢀILsꢀbasedꢀonꢀ1,1,3,3‐tetra‐alkylguani‐
1
13
ꢀ
lessꢀ viscousꢀ liquid.ꢀ Moreover,ꢀ H/ Cꢀ NMRꢀ characterizationꢀ
dataꢀwereꢀobtained.ꢀ
dineꢀ (Schemeꢀ 1),ꢀ whichꢀ wasꢀ appliedꢀ inꢀ theꢀ carbonylationꢀ ofꢀ
epoxides.ꢀNotably,ꢀitꢀwasꢀobservedꢀthatꢀ3aꢀexhibitedꢀtheꢀbestꢀ
catalyticꢀactivityꢀwithoutꢀtheꢀaidꢀofꢀaꢀbaseꢀasꢀanꢀadditiveꢀasꢀwellꢀ
asꢀperfectꢀrecyclability.ꢀ
Theꢀ 1,1,3,3‐tetra‐alkylguanidineꢀ cobaltꢀ carbonylꢀ ILsꢀ (com‐
poundsꢀ3a–3d)ꢀwereꢀsynthesizedꢀbyꢀtheꢀreactionꢀofꢀKCo(CO)4ꢀ
withꢀ 1,1,3,3‐tetra‐alkylguanidineꢀ chlorideꢀ salts.ꢀ Aꢀ 50‐mLꢀ
SchlenkꢀflaskꢀcontainingꢀmilledꢀKOHꢀ(6.0ꢀmmol)ꢀandꢀCo (CO)8ꢀ
2
2
.ꢀ ꢀ Experimentalꢀ
(1.0ꢀ mmol)ꢀ wasꢀplacedꢀinꢀtheꢀ gloveꢀbox.ꢀThen,ꢀ6.0ꢀmLꢀofꢀ de‐
gassedꢀ THFꢀ wasꢀ slowlyꢀ drippedꢀ intoꢀ theꢀ flaskꢀ underꢀ stirring,ꢀ
andꢀtheꢀstirringꢀwasꢀcontinuedꢀforꢀ2ꢀh.ꢀSubsequently,ꢀtheꢀsu‐
pernatantꢀwasꢀtransferredꢀtoꢀanotherꢀSchlenkꢀflaskꢀcontainingꢀ
1.1ꢀ mmolꢀ 1,1,3,3‐tetra‐alkylguanidineꢀ chlorideꢀ salt.ꢀ Theꢀ reac‐
tionꢀwasꢀcontinuedꢀforꢀ8ꢀhꢀunderꢀstirring.ꢀTheꢀTHFꢀsolventꢀwasꢀ
2.1.ꢀ ꢀ Generalꢀ ꢀ ꢀ
Allꢀtheꢀorganometallicꢀmanipulationsꢀwereꢀ performedꢀinꢀaꢀ
gloveꢀ boxꢀ orꢀ underꢀ aꢀ N ꢀ atmosphereꢀ usingꢀ standardꢀ Schlenkꢀ
2
techniques.ꢀ Unlessꢀ otherwiseꢀ noted,ꢀ allꢀ theꢀ reagentsꢀ wereꢀ ofꢀ
analyticalꢀ gradeꢀ andꢀ wereꢀ usedꢀ asꢀ received.ꢀ Tetrahydrofuranꢀ
thenꢀremovedꢀwithꢀaꢀvacuumꢀpump.ꢀNext,ꢀ6.0ꢀmLꢀCH
2
Cl ꢀwasꢀ
2
addedꢀintoꢀtheꢀ flaskꢀunderꢀanꢀ Arꢀatmosphere.ꢀAfterward,ꢀ theꢀ
mixtureꢀwasꢀfilteredꢀunderꢀanꢀArꢀatmosphere,ꢀandꢀtheꢀsolventꢀ
wasꢀremovedꢀinꢀvacuoꢀtoꢀobtainꢀtheꢀdesiredꢀproductsꢀ3ꢀasꢀlightꢀ
(
THF),ꢀ dichloromethane,ꢀ ethanol,ꢀ andꢀ propyleneꢀ oxideꢀ wereꢀ
purgedꢀwithꢀargonꢀtoꢀeliminateꢀtheꢀdissolvedꢀoxygenꢀandꢀwereꢀ
driedꢀtoꢀremoveꢀwater.ꢀCo (CO) ꢀwasꢀpreparedꢀbyꢀourꢀresearchꢀ
groupꢀaccordingꢀtoꢀtheꢀmethodꢀdescribedꢀinꢀaꢀpreviousꢀreportꢀ
2
8
orꢀdark‐blueꢀviscousꢀoilyꢀliquids.ꢀTheꢀ1,1,3,3‐tetra‐
ꢀ
alkylguani‐
dineꢀcobaltꢀcarbonylꢀILsꢀwereꢀallꢀcharacterizedꢀusingꢀIR,ꢀultra‐
1
13
[
33].ꢀ Infraredꢀ (IR)ꢀ spectraꢀ wereꢀ recordedꢀ onꢀ aꢀ Brukerꢀ
violet‐visibleꢀ(UV‐Vis)ꢀspectroscopy,ꢀ HꢀNMR,ꢀ CꢀNMR,ꢀHRMSꢀ
(ESI),ꢀTG‐DSC,ꢀandꢀDSC.ꢀ
1
IFS120HRꢀspectrophotometer.ꢀ Hꢀnuclearꢀmagneticꢀresonanceꢀ
(
13
NMR)ꢀandꢀ CꢀNMRꢀspectraꢀwereꢀmeasuredꢀonꢀBrukerꢀAvanceꢀ
IIIꢀ (400ꢀ MHz)ꢀ spectrometers.ꢀ High‐resolutionꢀ massꢀ
spectrometryꢀ (HRMS)ꢀ analysesꢀ wereꢀ performedꢀ onꢀ aꢀ Brukerꢀ
Microꢀ TOF‐QIIꢀ massꢀ instrumentꢀ withꢀ electrosprayꢀ ionizationꢀ
2.3.ꢀ ꢀ CharacterizationꢀdataꢀforꢀcobaltꢀcarbonylꢀILsꢀbasedꢀonꢀ
1,1,3,3‐tetra‐alkylguanidineꢀ
(
ESI)ꢀinꢀtheꢀpositiveꢀionizationꢀandꢀnegativeꢀmodeꢀonꢀsamplesꢀ
3aꢀ0.27ꢀg,ꢀ86%;ꢀT
g
:ꢀ–77ꢀ°C;ꢀthermalꢀdecompositionꢀtemper‐

−1
1
dissolvedꢀ inꢀ methanol.ꢀ Theꢀ glassꢀ transitionꢀ temperatureꢀ (T )ꢀ
g
ature:ꢀ215ꢀ°C;ꢀselectedꢀvmax/cm ꢀ(KBr)ꢀ1882ꢀvsꢀ(Co(CO)
NMRꢀ(400ꢀMHz,ꢀDMSO‐d
4H),ꢀ2.90ꢀ(s,ꢀ6H),ꢀ1.10ꢀ(t,ꢀJꢀ=ꢀ7.1ꢀHz,ꢀ6H);ꢀ CꢀNMRꢀ(100ꢀMHz,ꢀ
4
);ꢀ Hꢀ
wasꢀ determinedꢀ onꢀ aꢀ Mettler‐Toledoꢀ differentialꢀ scanningꢀ
calorimeterꢀ(modelꢀDSCꢀ822e)ꢀatꢀaꢀscanꢀrateꢀofꢀ10ꢀ°C/min.ꢀTheꢀ
thermalꢀ decompositionꢀ temperatureꢀ wasꢀ characterizedꢀ onꢀ aꢀ
Netzschꢀ STA449F3ꢀ thermogravimetricꢀ differentialꢀ scanningꢀ
calorimeterꢀ(TG‐DSC)ꢀatꢀaꢀscanꢀrateꢀofꢀ10ꢀ°C/min.ꢀ
6
):ꢀδꢀ7.93ꢀ(s,ꢀ2H),ꢀ3.27ꢀ(q,ꢀJꢀ=ꢀ7.1ꢀHz,ꢀ
13
6
DMSO‐d ):ꢀ δꢀ 160.6,ꢀ 43.1,ꢀ 39.4,ꢀ 12.5;ꢀ HRMSꢀ (ESI)ꢀ positiveꢀ ion:ꢀ
+
m/zꢀ 144.1488ꢀ (C
7
H
18
N
3
);ꢀ HRMSꢀ (ESI)ꢀ negativeꢀ ion:ꢀ m/zꢀ
),ꢀ 142.9199ꢀ (Co(CO)

),ꢀ 114.9254ꢀ
170.9135ꢀ (Co(CO)
4
3

(
Co(CO)
2
).ꢀ
2
1
.2.ꢀ ꢀ SynthesisꢀofꢀcobaltꢀcarbonylꢀILsꢀbasedꢀonꢀ
,1,3,3‐tetra‐alkylguanidineꢀ
3bꢀ0.30ꢀg,ꢀ81%;ꢀT
g
:ꢀ–65ꢀ°C;ꢀthermalꢀdecompositionꢀtemper‐

−1
1
ature:ꢀ207ꢀ°C;ꢀselectedꢀvmax/cm ꢀ(KBr)ꢀ1886ꢀvsꢀ(Co(CO)
NMRꢀ (400ꢀMHz,ꢀDMSO‐d
4H),ꢀ2.89ꢀ(s,ꢀ6H),ꢀ1.54–1.39ꢀ(m,ꢀ4H),ꢀ1.23ꢀ(dt,ꢀJꢀ=ꢀ14.8,ꢀ7.5ꢀHz,ꢀ
4H),ꢀ0.87ꢀ(t,ꢀJꢀ=ꢀ7.3ꢀHz,ꢀ6H);ꢀ CꢀNMRꢀ(100ꢀMHz,ꢀDMSO‐d ):ꢀδꢀ
161.1,ꢀ48.2,ꢀ39.3,ꢀ28.8,ꢀ19.1,ꢀ13.5;ꢀHRMSꢀ(ESI)ꢀpositiveꢀion:ꢀm/zꢀ
4
);ꢀ Hꢀ
6
):ꢀδꢀ7.96ꢀ(s,ꢀ2H),ꢀ3.20ꢀ(t,ꢀJꢀ=ꢀ7.0ꢀHz,ꢀ
Compoundꢀ1ꢀ(1,1,3,3‐tetra‐alkylguanidine)ꢀwasꢀsynthesizedꢀ
13
accordingꢀtoꢀtheꢀmethodꢀdescribedꢀinꢀtheꢀRef.ꢀ[34]ꢀusingꢀdime‐
thylꢀcyanamideꢀandꢀdiamineꢀasꢀtheꢀstartingꢀmaterials.ꢀMoreo‐
6
NH
NH
NH2 Cl
1
2
R1
NH
a
b
c
R = R = Et
R1
R1
R1
HCl
KCo(CO)4
1
2
N
N
R2
Co(CO)4
R = R = n-C H
4 9
N C N +
N
N
N
N
1
2
R = R = -(CH ) -
R2
R2
R2
2 4
1
2
d
R = R = -(CH2)5-
1
2
3
Schemeꢀ1.ꢀSyntheticꢀroutesꢀandꢀstructuresꢀofꢀ1,1,3,3‐tetra‐alkylguanidineꢀcobaltꢀcarbonylꢀILs.ꢀ

ꢀ
WeiꢀZhangꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ805–812ꢀ
807ꢀ
+
2
00.2120ꢀ(C11
H N
26 3
);ꢀHRMSꢀ(ESI)ꢀnegativeꢀion:ꢀm/zꢀ170.9135ꢀ
173.1,ꢀ69.3,ꢀ60.6,ꢀ40.9,ꢀ29.4,ꢀ14.2,ꢀ9.8.ꢀ



(Co(CO)
4
),ꢀ142.9203ꢀ(Co(CO)
cꢀ0.25ꢀg,ꢀ80%;ꢀT
ature:ꢀ208ꢀ°C;ꢀselectedꢀvmax/cm−1ꢀ(KBr)ꢀ1882ꢀvsꢀ(Co(CO)
NMRꢀ (400ꢀMHz,ꢀDMSO‐d
3
),ꢀ114.9254ꢀ(Co(CO)
2
).ꢀ
Ethylꢀ 3‐hydroxyheptanoateꢀ (4c).ꢀ Thisꢀ compoundꢀ wasꢀ pre‐
paredꢀusingꢀtheꢀgeneralꢀprocedureꢀdescribedꢀaboveꢀandꢀpuri‐
fiedꢀ byꢀ flashꢀ columnꢀ chromatographyꢀ toꢀ giveꢀ aꢀ colorlessꢀ oil,ꢀ
3
g
:ꢀ–60ꢀ°C;ꢀthermalꢀdecompositionꢀtemper‐

1
4
);ꢀ Hꢀ
ꢀ1
6
):ꢀδꢀ7.62ꢀ(s,ꢀ2H),ꢀ3.39ꢀ(t,ꢀJꢀ=ꢀ6.4ꢀHz,ꢀ
0.77ꢀg,ꢀ89%ꢀyield. HꢀNMRꢀ(400ꢀMHz,ꢀCDCl ):ꢀδꢀ4.15ꢀ(q,ꢀJꢀ=ꢀ7.1ꢀ
3
13
4
H),ꢀ2.91ꢀ(s,ꢀ6H),ꢀ1.86ꢀ(dd,ꢀJꢀ=ꢀ7.8,ꢀ5.1ꢀHz,ꢀ4H);ꢀ CꢀNMRꢀ(100ꢀ
Hz,ꢀ2H),ꢀ4.05–3.92ꢀ(m,ꢀ1H),ꢀ2.92ꢀ(s,ꢀ1H),ꢀ2.48ꢀ(dd,ꢀJꢀ=ꢀ16.4,ꢀ3.2ꢀ
Hz,ꢀ 1H),ꢀ 2.38ꢀ (dd,ꢀ Jꢀ =ꢀ 16.4,ꢀ 9.0ꢀ Hz,ꢀ 1H),ꢀ 1.56–1.43ꢀ (m,ꢀ 2H),ꢀ
1.42–1.34ꢀ(m,ꢀ2H),ꢀ1.34–1.29ꢀ(m,ꢀ2H),ꢀ1.26ꢀ(dd,ꢀJꢀ=ꢀ8.9,ꢀ5.4ꢀHz,ꢀ
3H),ꢀ 0.92–0.86ꢀ (m,ꢀ 3H);ꢀ13Cꢀ NMRꢀ (100ꢀ MHz,ꢀ CDCl
68.0,ꢀ60.6,ꢀ41.3,ꢀ36.2,ꢀ29.7,ꢀ27.6,ꢀ22.6,ꢀ14.1.ꢀ
MHz,ꢀDMSO‐d
6
):ꢀδꢀ158.1,ꢀ49.2,ꢀ39.4,ꢀ24.9;ꢀHRMSꢀ(ESI)ꢀpositiveꢀ
+
ion:ꢀ m/zꢀ 142.1342ꢀ (C
70.9134ꢀ (Co(CO)
Co(CO)
).ꢀ
dꢀ0.27ꢀg,ꢀ83%;ꢀT
7
H
16
N
3
);ꢀ HRMSꢀ (ESI)ꢀ negativeꢀ ion:ꢀ m/zꢀ
),ꢀ 142.9196ꢀ (Co(CO)

),ꢀ 114.9249ꢀ
1
(
4
3
3
):ꢀ δꢀ 173.1,ꢀ
2
3
g
:ꢀ–55ꢀ°C;ꢀthermalꢀdecompositionꢀtemper‐
3‐Hydroxyhept‐6‐enoicꢀ acidꢀ ethylꢀ esterꢀ (4d).ꢀ Thisꢀ com‐
poundꢀ wasꢀ preparedꢀ usingꢀ theꢀ generalꢀ procedureꢀ describedꢀ

−1
1
ature:ꢀ202ꢀ°C;ꢀselectedꢀvmax/cm ꢀ(KBr)ꢀ1879ꢀvsꢀ(Co(CO)
4
);ꢀ Hꢀ
NMRꢀ(400ꢀMHz,ꢀDMSO‐d
6
):ꢀδꢀ7.82ꢀ(s,ꢀ2H),ꢀ3.25ꢀ(d,ꢀJꢀ=ꢀ5.1ꢀHz,ꢀ
aboveꢀandꢀpurifiedꢀbyꢀflashꢀcolumnꢀchromatographyꢀtoꢀgiveꢀaꢀ
13
ꢀ1
4
1
1
H),ꢀ2.91ꢀ(s,ꢀ6H),ꢀ1.59ꢀ(s,ꢀ6H);ꢀ CꢀNMRꢀ(100ꢀMHz,ꢀDMSO‐d
60.4,ꢀ 48.6,ꢀ 39.3,ꢀ 25.0,ꢀ 23.3;ꢀ HRMSꢀ (ESI)ꢀ positiveꢀ ion:ꢀ m/zꢀ
6
):ꢀδꢀ
colorlessꢀ oil,ꢀ 0.69ꢀ g,ꢀ 80%ꢀ yield. Hꢀ NMRꢀ (400ꢀ MHz,ꢀ CDCl
3
):ꢀ δꢀ
5.91–5.67ꢀ (m,ꢀ 1H),ꢀ 5.12–4.92ꢀ (m,ꢀ 2H),ꢀ 4.23–4.07ꢀ (m,ꢀ 2H),ꢀ
+
56.1489ꢀ(C
H N
8 18 3
);ꢀHRMSꢀ(ESI)ꢀnegativeꢀion:ꢀm/zꢀ170.9132ꢀ
4.07–3.92ꢀ(m,ꢀ1H),ꢀ3.04ꢀ(s,ꢀ1H),ꢀ2.55–2.35ꢀ(m,ꢀ2H),ꢀ2.28–2.01ꢀ



13
(
Co(CO)
4
),ꢀ142.9204ꢀ(Co(CO)
3
),ꢀ114.9253ꢀ(Co(CO)
2
).ꢀ
(m,ꢀ2H),ꢀ1.72–1.41ꢀ(m,ꢀ2H),ꢀ1.30–1.21ꢀ(m,ꢀ3H);ꢀ CꢀNMRꢀ(100ꢀ
MHz,ꢀCDCl ):ꢀδꢀ173.0,ꢀ138.1,ꢀ115.0,ꢀ77.4,ꢀ77.0,ꢀ76.7,ꢀ67.4,ꢀ60.7,ꢀ
3
2.4.ꢀ ꢀ CatalyticꢀactivityꢀofꢀcobaltꢀcarbonylꢀILsꢀbasedꢀonꢀ
41.3,ꢀ35.6,ꢀ29.7,ꢀ14.2.ꢀ
1
,1,3,3‐tetra‐alkylguanidineꢀinꢀtheꢀcarbonylationꢀofꢀepoxideꢀ
4‐Butoxy‐3‐hydroxybutyricꢀacidꢀethylꢀesterꢀ(4e).ꢀThisꢀcom‐
poundꢀ wasꢀ preparedꢀ usingꢀ theꢀ generalꢀ procedureꢀ describedꢀ
aboveꢀandꢀpurifiedꢀbyꢀflashꢀcolumnꢀchromatographyꢀtoꢀgiveꢀaꢀ
Theꢀ catalyticꢀ activityꢀ ofꢀ theꢀ cobaltꢀ carbonylꢀ ILsꢀ basedꢀ onꢀ
,1,3,3‐tetra‐alkylguanidineꢀ inꢀ theꢀ reactionꢀ ofꢀ ring‐openingꢀ
ꢀ
1
1
colorlessꢀ oil,ꢀ 0.94ꢀ g,ꢀ 92%ꢀ yield. Hꢀ NMRꢀ (400ꢀ MHz,ꢀ CDCl ):ꢀ δꢀ
3
carbonylationꢀ ofꢀ epoxidesꢀ wasꢀ investigated.ꢀ Inꢀ ourꢀ test,ꢀ weꢀ
observedꢀthatꢀtheꢀcompoundsꢀ3a–3d,ꢀespeciallyꢀ3a,ꢀwithoutꢀtheꢀ
aidꢀofꢀaꢀbaseꢀadditive,ꢀexhibitedꢀrelativelyꢀgoodꢀcatalyticꢀactivityꢀ
inꢀtheꢀreactionꢀofꢀalkoxycarbonylationꢀofꢀepoxidesꢀ(Schemeꢀ2).ꢀ
Theꢀreactionꢀwasꢀconductedꢀinꢀaꢀ50‐mLꢀstainlessꢀsteelꢀauto‐
claveꢀequippedꢀwithꢀaꢀstirringꢀmagnet.ꢀTheꢀreactorꢀwasꢀchargedꢀ
withꢀethanolꢀ(3.0ꢀmL),ꢀepoxideꢀ(5.0ꢀmmol),ꢀandꢀcatalystꢀ3aꢀ(3ꢀ
mol%).ꢀThen,ꢀtheꢀreactorꢀwasꢀpressurizedꢀwithꢀ6.0ꢀMPaꢀCOꢀandꢀ
heatedꢀtoꢀ80ꢀ°C.ꢀAfterꢀcompletionꢀofꢀtheꢀreaction,ꢀtheꢀautoclaveꢀ
wasꢀcooledꢀwithꢀiceꢀwaterꢀandꢀslowlyꢀdepressurizedꢀtoꢀatmos‐
phericꢀpressure.ꢀTheꢀproductꢀmixtureꢀunderwentꢀsimpleꢀflashꢀ
columnꢀchromatographyꢀtoꢀdisposeꢀofꢀtheꢀILsꢀcatalystꢀandꢀwasꢀ
thenꢀanalyzedꢀusingꢀgasꢀchromatographyꢀ(GC)ꢀandꢀGC‐MS.ꢀ ꢀ
Theꢀstructuresꢀandꢀpuritiesꢀofꢀtheꢀproductsꢀwereꢀfullyꢀchar‐
acterizedꢀ usingꢀ NMRꢀ spectroscopy.ꢀ Analyticalꢀ dataꢀ forꢀ theseꢀ
compoundsꢀareꢀlistedꢀbelow.ꢀ
4.25–4.12ꢀ(m,ꢀ3H),ꢀ3.52–3.37ꢀ(m,ꢀ4H),ꢀ3.11ꢀ(d,ꢀJꢀ=ꢀ77.9ꢀHz,ꢀ1H),ꢀ
2.53ꢀ(d,ꢀJꢀ=ꢀ6.3ꢀHz,ꢀ2H),ꢀ1.61–1.51ꢀ(m,ꢀ2H),ꢀ1.43–1.31ꢀ(m,ꢀ2H),ꢀ
1.28ꢀ(t,ꢀJꢀ=ꢀ7.1ꢀHz,ꢀ3H),ꢀ0.92ꢀ(t,ꢀJꢀ=ꢀ7.4ꢀHz,ꢀ3H);ꢀ13CꢀNMRꢀ(100ꢀ
3
MHz,ꢀ CDCl ):ꢀ δꢀ 172.2,ꢀ 73.7,ꢀ 71.3,ꢀ 67.2,ꢀ 60.7,ꢀ 38.3,ꢀ 31.7,ꢀ 19.3,ꢀ
14.2,ꢀ13.9.ꢀ
3‐Hydroxy‐4‐phenoxybutyricꢀ acidꢀ ethylꢀ esterꢀ (4f).ꢀ Thisꢀ
compoundꢀ wasꢀ preparedꢀ usingꢀ theꢀ generalꢀ procedureꢀ de‐
scribedꢀaboveꢀandꢀpurifiedꢀbyꢀflashꢀcolumnꢀchromatographyꢀtoꢀ
1
giveꢀ aꢀ colorlessꢀ oil,ꢀ 0.94ꢀ g,ꢀ 84%ꢀ yield.ꢀ Hꢀ NMRꢀ (400ꢀ MHz,ꢀ
CDCl ):ꢀδꢀ7.26ꢀ(s,ꢀ2H),ꢀ7.00–6.95ꢀ(m,ꢀ1H),ꢀ6.91ꢀ(dd,ꢀJꢀ=ꢀ11.4,ꢀ3.6ꢀ
3
Hz,ꢀ2H),ꢀ4.48–4.37ꢀ(m,ꢀ1H),ꢀ4.23–4.16ꢀ(m,ꢀ2H),ꢀ4.00ꢀ(d,ꢀJꢀ=ꢀ5.3ꢀ
Hz,ꢀ2H),ꢀ3.10ꢀ(d,ꢀJꢀ=ꢀ33.6ꢀHz,ꢀ1H),ꢀ2.68ꢀ(dd,ꢀJꢀ=ꢀ9.7,ꢀ5.5ꢀHz,ꢀ2H),ꢀ
1.30–1.27ꢀ(m,ꢀ3H);ꢀ13CꢀNMRꢀ(100ꢀMHz,ꢀCDCl
3
):ꢀδꢀ172.1,ꢀ158.4,ꢀ
129.5,ꢀ121.2,ꢀ114.6,ꢀ70.6,ꢀ66.8,ꢀ60.9,ꢀ38.1,ꢀ14.2.ꢀ
4‐Butyryloxy‐3‐hydroxybutyricꢀ acidꢀ ethylꢀ esterꢀ (4g).ꢀ Thisꢀ
compoundꢀ wasꢀ preparedꢀ usingꢀ theꢀ generalꢀ procedureꢀ de‐
scribedꢀaboveꢀandꢀpurifiedꢀbyꢀflashꢀcolumnꢀchromatographyꢀtoꢀ
Ethylꢀ 3‐hydroxybutyrateꢀ (4a).ꢀ Thisꢀ compoundꢀ wasꢀ pre‐
paredꢀusingꢀtheꢀgeneralꢀprocedureꢀdescribedꢀaboveꢀandꢀpuri‐
fiedꢀ byꢀ flashꢀ columnꢀ chromatographyꢀ toꢀ giveꢀ aꢀ colorlessꢀ oil,ꢀ
1
giveꢀ aꢀ colorlessꢀ oil,ꢀ 0.86ꢀ g,ꢀ 79%ꢀ yield.ꢀ Hꢀ NMRꢀ (400ꢀ MHz,ꢀ
CDCl ):ꢀ δꢀ 4.29ꢀ (td,ꢀ Jꢀ =ꢀ 11.7,ꢀ 6.1ꢀ Hz,ꢀ 1H),ꢀ 4.24–4.16ꢀ (m,ꢀ 2H),ꢀ
3
ꢀ
1
0
.54ꢀg,ꢀ81%ꢀyield. HꢀNMRꢀ(400ꢀMHz,ꢀCDCl
3
):ꢀδꢀ4.31–4.05ꢀ(m,ꢀ
4.17–4.03ꢀ (m,ꢀ 2H),ꢀ 3.36–2.80ꢀ (m,ꢀ 1H),ꢀ 2.74–2.45ꢀ (m,ꢀ 2H),ꢀ
2.40–2.27ꢀ(m,ꢀ2H),ꢀ1.73–1.62ꢀ(m,ꢀ2H),ꢀ1.32–1.25ꢀ(m,ꢀ3H),ꢀ0.96ꢀ
3
H),ꢀ2.79ꢀ(s,ꢀ1H),ꢀ2.46ꢀ(qd,ꢀJꢀ=ꢀ16.4,ꢀ6.1ꢀHz,ꢀ2H),ꢀ1.28ꢀ(t,ꢀJꢀ=ꢀ7.1ꢀ
13
(t,ꢀJꢀ=ꢀ7.4ꢀHz,ꢀ3H);ꢀ13CꢀNMRꢀ(100ꢀMHz,ꢀCDCl
):ꢀδꢀ173.6,ꢀ172.0,ꢀ
Hz,ꢀ3H),ꢀ1.23ꢀ(d,ꢀJꢀ=ꢀ6.3ꢀHz,ꢀ3H);ꢀ CꢀNMRꢀ(100ꢀMHz,ꢀCDCl
73.0,ꢀ64.3,ꢀ60.7,ꢀ42.8,ꢀ22.4,ꢀ14.2.ꢀ
Ethylꢀ3‐hydroxyvalerateꢀ(4b).ꢀThisꢀcompoundꢀwasꢀpreparedꢀ
3
):ꢀδꢀ
3
1
66.9,ꢀ66.4,ꢀ61.0,ꢀ37.9,ꢀ36.0,ꢀ18.4,ꢀ14.2,ꢀ13.7.ꢀ
Ethyl‐4‐chloro‐3‐hydroxybutyrateꢀ (4h).ꢀ Thisꢀ compoundꢀ
usingꢀtheꢀgeneralꢀprocedureꢀdescribedꢀaboveꢀandꢀpurifiedꢀbyꢀ
flashꢀ columnꢀ chromatographyꢀ toꢀ giveꢀ aꢀ colorlessꢀ oil,ꢀ 0.66ꢀ g,ꢀ
wasꢀpreparedꢀusingꢀtheꢀgeneralꢀprocedureꢀdescribedꢀaboveꢀandꢀ
purifiedꢀbyꢀflashꢀcolumnꢀchromatographyꢀtoꢀgiveꢀaꢀcolorlessꢀoil,ꢀ
ꢀ1
1
9
4
2
0%ꢀyield. HꢀNMRꢀ(400ꢀMHz,ꢀCDCl
.02–3.85ꢀ(m,ꢀ1H),ꢀ2.89ꢀ(s,ꢀ1H),ꢀ2.49ꢀ(dd,ꢀJꢀ=ꢀ16.4,ꢀ3.1ꢀHz,ꢀ1H),ꢀ
.38ꢀ(dd,ꢀJꢀ=ꢀ16.4,ꢀ9.1ꢀHz,ꢀ1H),ꢀ1.62–1.39ꢀ(m,ꢀ2H),ꢀ1.26ꢀ(t,ꢀJꢀ=ꢀ7.1ꢀ
3
):ꢀδꢀ4.16ꢀ(q,ꢀJꢀ=ꢀ7.1ꢀHz,ꢀ2H),ꢀ
0.58ꢀg,ꢀ70%ꢀyield.ꢀ HꢀNMRꢀ(400ꢀMHz,ꢀCDCl
3
):ꢀδꢀ4.30–4.22ꢀ(m,ꢀ
1H),ꢀ 4.22–4.13ꢀ (m,ꢀ 2H),ꢀ 3.66–3.54ꢀ (m,ꢀ 2H),ꢀ 3.14ꢀ (s,ꢀ 1H),ꢀ
2.68–2.56ꢀ (m,ꢀ 2H),ꢀ 1.35–1.20ꢀ (m,ꢀ 3H);ꢀ 13Cꢀ NMRꢀ (100ꢀ MHz,ꢀ
Hz,ꢀ3H),ꢀ0.95ꢀ(t,ꢀJꢀ=ꢀ7.5ꢀHz,ꢀ3H);ꢀ13CꢀNMRꢀ(100ꢀMHz,ꢀCDCl
CDCl ):ꢀδꢀ171.8,ꢀ68.0,ꢀ61.0,ꢀ48.1,ꢀ38.5,ꢀ14.1.ꢀ
3
):ꢀδꢀ
3
Ethyl‐3‐hydroxy‐3‐phenylꢀ propionateꢀ (4i).ꢀ Thisꢀ compoundꢀ
wasꢀpreparedꢀusingꢀtheꢀgeneralꢀprocedureꢀdescribedꢀaboveꢀandꢀ
cobalt carbonyl ILs based
on tetra-alkylguanidine
OH
O
O
+
CO + EtOH
purifiedꢀbyꢀflashꢀcolumnꢀchromatographyꢀtoꢀgiveꢀaꢀcolorlessꢀoil,ꢀ
R
R
O
1
Schemeꢀ2.ꢀAlkoxycarbonylationꢀofꢀepoxides.ꢀ
3
0.39ꢀg,ꢀ40%ꢀyield.ꢀ HꢀNMRꢀ(400ꢀMHz,ꢀCDCl ):ꢀδꢀ4.30–4.22ꢀ(m,ꢀ

808ꢀ
WeiꢀZhangꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ805–812ꢀ
1
2
CDCl
H),ꢀ 4.22–4.13ꢀ (m,ꢀ 2H),ꢀ 3.66–3.54ꢀ (m,ꢀ 2H),ꢀ 3.14ꢀ (s,ꢀ 1H),ꢀ
.68–2.56ꢀ (m,ꢀ 2H),ꢀ 1.35–1.20ꢀ (m,ꢀ 3H);ꢀ 13Cꢀ NMRꢀ (100ꢀ MHz,ꢀ
):ꢀδꢀ172.4,ꢀ142.5,ꢀ128.6,ꢀ127.8,ꢀ125.7,ꢀ70.3,ꢀ60.9,ꢀ43.4,ꢀ14.2.ꢀ
‐Hydroxy‐4‐phenylbutyricꢀacidꢀethylꢀesterꢀ(4j).ꢀThisꢀcom‐
Tableꢀ1ꢀ
Tgꢀvaluesꢀofꢀ3a–3d.ꢀ
3
Compoundꢀ
/°Cꢀ
3aꢀ
−77ꢀ
3bꢀ
3cꢀ
3dꢀ
3
T
g
−65ꢀ
−60ꢀ
−55ꢀ
poundꢀ wasꢀ preparedꢀ usingꢀ theꢀ generalꢀ procedureꢀ describedꢀ
aboveꢀandꢀpurifiedꢀbyꢀflashꢀcolumnꢀchromatographyꢀtoꢀgiveꢀaꢀ
ꢀ
indicatingꢀ aꢀ distortionꢀ ofꢀ theꢀ anionꢀ Co(CO)
4
ꢀ fromꢀ idealꢀ T
ꢀ
d
ꢀ
1
colorlessꢀ oil,ꢀ 0.74ꢀ g,ꢀ 71%ꢀ yield. Hꢀ NMRꢀ (400ꢀ MHz,ꢀ CDCl
.56–6.95ꢀ(m,ꢀ5H),ꢀ4.33–4.21ꢀ(m,ꢀ1H),ꢀ4.21–4.07ꢀ(m,ꢀ2H),ꢀ3.01ꢀ
d,ꢀJꢀ=ꢀ33.8ꢀHz,ꢀ1H),ꢀ2.87ꢀ(dd,ꢀJꢀ=ꢀ13.6,ꢀ7.1ꢀHz,ꢀ1H),ꢀ2.76ꢀ(dd,ꢀJꢀ=ꢀ
3.6,ꢀ 6.2ꢀ Hz,ꢀ 1H),ꢀ 2.58–2.35ꢀ (m,ꢀ 2H),ꢀ 1.31–1.22ꢀ (m,ꢀ 3H);ꢀ 13Cꢀ
NMRꢀ (100ꢀ MHz,ꢀ CDCl ):ꢀ δꢀ 172.7,ꢀ 137.7,ꢀ 129.5,ꢀ 128.5,ꢀ 126.6,ꢀ
9.1,ꢀ60.7,ꢀ43.0,ꢀ40.5,ꢀ14.2.ꢀ
3
):ꢀ δꢀ
symmetry.ꢀ Thisꢀ distortionꢀ couldꢀ beꢀ causedꢀ byꢀ theꢀ hydrogenꢀ
bondsꢀ [22,37–38],ꢀ andꢀ theꢀ appearanceꢀ ofꢀ theseꢀ forbiddenꢀ
bandsꢀprovidesꢀaꢀreliableꢀmeasureꢀtoꢀconfirmꢀtheꢀexistenceꢀofꢀ
theseꢀdistortionsꢀinꢀcrystallineꢀcharge‐transferꢀsalts,ꢀwhichꢀhasꢀ
beenꢀpreviouslyꢀillustratedꢀbyꢀBockmanꢀetꢀal.ꢀ[37].ꢀMoreover,ꢀ
theꢀmostꢀdistortedꢀanionꢀoutꢀofꢀtheꢀfourꢀsaltsꢀisꢀapparentꢀbe‐
causeꢀofꢀtheꢀcloseꢀproximityꢀofꢀtheꢀanion/cationꢀpairsꢀ(Fig.ꢀ1).ꢀ
7
(
1
3
6
3.ꢀ ꢀ Resultsꢀandꢀdiscussionꢀ
3
.1.3.ꢀ ꢀ Meltingꢀpointꢀandꢀstabilityꢀ
TheꢀthermalꢀbehaviorꢀofꢀtheꢀfourꢀILsꢀsaltsꢀ3a–3dꢀwasꢀana‐
3
1
.1.ꢀ ꢀ CharacterizationꢀofꢀcobaltꢀcarbonylꢀILsꢀbasedꢀonꢀ
,1,3,3‐tetra‐alkylguanidineꢀ ꢀ
lyzedꢀ usingꢀ DSCꢀ andꢀ TG‐DSCꢀ techniques,ꢀ andꢀ theꢀ T ꢀ dataꢀ areꢀ
g
listedꢀinꢀTableꢀ1.ꢀForꢀallꢀfourꢀcompounds,ꢀtheꢀglassꢀtransitionꢀ
temperatureꢀwasꢀapproximatelyꢀ−60ꢀ°C,ꢀindicatingꢀthatꢀtheyꢀareꢀ
room‐temperatureꢀILs.ꢀ ꢀ
Theꢀ thermalꢀ stabilityꢀ ofꢀ theꢀ fourꢀ compoundsꢀ wasꢀ alsoꢀ
measuredꢀ usingꢀ thermogravimetricꢀ analysis.ꢀ Theꢀ TG‐DSCꢀ
curvesꢀ (Fig.ꢀ 2)ꢀ revealꢀ thatꢀ theꢀ fourꢀ ILsꢀ areꢀ quiteꢀ robustꢀ andꢀ
thermalꢀstable,ꢀandꢀtheirꢀdecompositionꢀtemperaturesꢀareꢀhighꢀ
3
.1.1.ꢀ ꢀ Miscibilityꢀ ꢀ
Theꢀ miscibilitiesꢀ ofꢀ theꢀ fourꢀ compoundsꢀ 3a–3dꢀ wereꢀ
qualitativelyꢀ determinedꢀ toꢀ beꢀ similarꢀ inꢀ severalꢀ commonꢀ
solvents.ꢀ Theyꢀ wereꢀ allꢀ wellꢀ dissolvedꢀ inꢀ moreꢀ polarꢀ organicꢀ
solventsꢀ suchꢀ asꢀ methanol,ꢀ ethanol,ꢀ dichloromethane,ꢀ
tetrahydrofuran,ꢀandꢀacetone,ꢀwhereasꢀtheyꢀwereꢀinsolubleꢀinꢀ
someꢀlessꢀpolarꢀsolventsꢀsuchꢀasꢀpetroleumꢀether,ꢀhexane,ꢀandꢀ
toluene,ꢀmostꢀlikelyꢀbecauseꢀofꢀtheꢀexistenceꢀofꢀtheꢀionicꢀbondꢀ
(approximatelyꢀ200ꢀ°C).ꢀItꢀisꢀclearꢀthatꢀtheꢀthermalꢀstabilityꢀofꢀ
compoundsꢀ3a–3dꢀsatisfiesꢀtheꢀrequirementsꢀofꢀmostꢀchemicalꢀ
reactionꢀsystems.ꢀ
[35].ꢀHowever,ꢀ noneꢀofꢀtheꢀ compoundsꢀcouldꢀbeꢀ dissolvedꢀinꢀ
chloroformꢀ despiteꢀ itsꢀ polarity.ꢀ Inꢀ addition,ꢀ allꢀ ofꢀ theꢀ
compoundsꢀwereꢀinsolubleꢀinꢀwater.ꢀ ꢀ
Becauseꢀ ofꢀ theꢀ existenceꢀ ofꢀ interionicꢀ hydrogenꢀ bondingꢀ
−1
ꢀ
(
whichꢀcanꢀbeꢀconfirmedꢀbyꢀtheꢀbandsꢀatꢀ~3450ꢀcm ꢀintheꢀIRꢀ
spectrumꢀinꢀFig.ꢀ1)ꢀ[22],ꢀtheꢀstabilityꢀofꢀcompoundsꢀ3a–3dꢀisꢀ
3
.1.2.ꢀ ꢀ IRꢀstudiesꢀ
TheꢀIRꢀspectraꢀofꢀallꢀfourꢀsaltsꢀrevealꢀaꢀstrongꢀbandꢀatꢀap‐

muchꢀbetterꢀthanꢀthatꢀofꢀconventionalꢀCo(CO)
4
ꢀsalts,ꢀsuchꢀasꢀ
NaCo(CO) ꢀandꢀKCo(CO)
4
4
.ꢀAfterꢀexposureꢀtoꢀairꢀforꢀ24ꢀhꢀatꢀroomꢀ
−
1
proximatelyꢀ 1880ꢀ cm ꢀ forꢀ theꢀ characteristicꢀ COꢀ absorption,ꢀ
alsoꢀindicatingꢀtheꢀpresenceꢀofꢀtheꢀCo(CO)
ever,ꢀ theꢀ spectraꢀ alsoꢀ containꢀ minorꢀ differences.ꢀ Withꢀ theꢀ
lengtheningꢀ ofꢀ theꢀ alkylꢀ chain,ꢀ theꢀ COꢀ absorptionꢀ (T )ꢀ bandꢀ
shiftsꢀtoꢀlowerꢀ wavenumbers,ꢀindictingꢀtheꢀeffectꢀofꢀ so‐calledꢀ
interionicꢀhydrogenꢀbondingꢀbetweenꢀionꢀpairsꢀ[22].ꢀTheꢀbandsꢀ
atꢀ~3450ꢀcm ꢀalsoꢀreflectꢀintermolecularꢀhydrogenꢀbands.ꢀInꢀ
eachꢀ infraredꢀ spectrumꢀ ofꢀ theꢀ fourꢀ preparedꢀ compounds,ꢀ theꢀ
symmetry‐forbiddenꢀ A ꢀ bandsꢀ atꢀ ∼2008ꢀ cm ꢀ areꢀ observed,ꢀ
temperature,ꢀ theꢀ physicalꢀ appearancesꢀ ofꢀ compoundsꢀ 3a–3dꢀ
wereꢀ unchanged.ꢀ Theꢀ IRꢀ spectraꢀ ofꢀ compoundꢀ 3aꢀ beforeꢀ theꢀ
reactionꢀandꢀafterꢀ4ꢀrunsꢀareꢀpresentedꢀinꢀFig.ꢀ3,ꢀandꢀthereꢀareꢀ
noꢀobviousꢀchanges.ꢀTheꢀcharacteristicꢀCOꢀabsorptionꢀbandꢀatꢀ

4
ꢀanionꢀ[36];ꢀhow‐
2
−1
ꢀbandꢀatꢀ∼2008ꢀcm−1ꢀ
~
1860ꢀcm ꢀandꢀsymmetry‐forbiddenꢀA
1
canꢀstillꢀbeꢀobservedꢀinꢀtheꢀIRꢀspectraꢀofꢀcompoundꢀ3aꢀafterꢀ4ꢀ
−1
−1
runs.ꢀ However,ꢀ theꢀ bandsꢀ atꢀ 3300–3500ꢀ cm ꢀ showꢀ slightꢀ
changes,ꢀ whichꢀ wereꢀmostꢀ likelyꢀcausedꢀbyꢀtheꢀpresenceꢀofꢀaꢀ
fewꢀ impurities.ꢀ Therefore,ꢀ thisꢀ resultꢀ alsoꢀ demonstratesꢀ theꢀ
stabilityꢀofꢀcatalystꢀ3a.ꢀ
−1
1
3
3
3
3
d
o
1
20
00
3a 215 C
4
2
0
TG
o
3
3
3
b 207 C
DSC
c
o
1
c 208 C
o
d 202 C
8
6
4
2
0
0
0
0
b
a
-2
-4
4000
3500
3000
2500
2000
1500
1000
500
-6
100
200
300
400

1
o
Wavenumber (cm )
Temperature ( C)
Fig.ꢀ1.ꢀIRꢀspectraꢀofꢀ3a–3d.ꢀ
Fig.ꢀ2.ꢀTG‐DSCꢀcurvesꢀofꢀ3a–3d.ꢀ

ꢀ
WeiꢀZhangꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ805–812ꢀ
Tableꢀ2ꢀ
809ꢀ
3
a after running 4 times
UV‐VisꢀabsorptionꢀbandsꢀofꢀKCo(CO)
4
ꢀandꢀ3a–3dꢀinꢀdichloromethane.ꢀ
3a
Compoundꢀ
UV‐Visꢀabsorptionꢀbandsꢀ(nm)ꢀ
KCo(CO)
4
ꢀ
233,ꢀ360(sh)ꢀ
229ꢀ
3
3
3
3
ꢀ
aꢀ
bꢀ
cꢀ
229ꢀ
229ꢀ
234ꢀ
dꢀ
1,1,3,3‐tetra‐alkylguanidineꢀinꢀtheꢀreactionꢀofꢀalkoxycarbonyla‐
tionꢀofꢀpropyleneꢀoxideꢀ(PO)ꢀwasꢀinvestigated.ꢀInꢀaddition,ꢀtheꢀ
reactionꢀ conditionsꢀ wereꢀ optimizedꢀ (Tableꢀ 3).ꢀ Uponꢀ treatingꢀ
theꢀsubstrateꢀPOꢀwithꢀ2ꢀmol%ꢀcatalystꢀ3a–3dꢀinꢀethanolꢀunderꢀ
COꢀ atmosphere,ꢀ theꢀ desiredꢀ productꢀ wasꢀ obtainedꢀ withꢀ littleꢀ
differenceꢀ inꢀ conversionꢀ orꢀ selectionꢀ (Tableꢀ 3,ꢀ entriesꢀ 1–4).ꢀ
Compoundsꢀ3a–3dꢀshowedꢀdistinctꢀcatalyticꢀactivity,ꢀwithꢀthatꢀ
ofꢀ3aꢀexhibitingꢀtheꢀoptimalꢀactivity.ꢀMoreover,ꢀgoodꢀcatalyticꢀ
activityꢀofꢀ3aꢀcouldꢀbeꢀachievedꢀwhenꢀethanolꢀwasꢀusedꢀasꢀbothꢀ
theꢀreactantꢀandꢀsolventꢀ(Tableꢀ3,ꢀentriesꢀ5–7)ꢀwithoutꢀaddingꢀ
otherꢀ solvents.ꢀ Theꢀ conversionꢀ ofꢀ POꢀ andꢀ yieldꢀ ofꢀ ethylꢀ
3‐hydroxybutyrateꢀ increasedꢀ withꢀ increasingꢀ catalystꢀ loadingꢀ
andꢀ changedꢀ slightlyꢀ whenꢀ theꢀ catalyst:POꢀ ratioꢀ wasꢀ greaterꢀ
thanꢀ3ꢀmol%ꢀ(Tableꢀ3,ꢀentriesꢀ5ꢀandꢀ8–10).ꢀTheꢀeffectꢀofꢀtem‐
peratureꢀonꢀthisꢀreactionꢀwasꢀsignificantꢀ(Tableꢀ3,ꢀentriesꢀ5ꢀandꢀ
11–13).ꢀ Withꢀ increasingꢀ temperature,ꢀ theꢀ POꢀ conversionꢀ
greatlyꢀ increased;ꢀ however,ꢀ theꢀ selectivityꢀ toꢀ ethylꢀ
3‐hydroxybutyrateꢀ decreasedꢀ whenꢀ theꢀ temperatureꢀ wasꢀ
aboveꢀ80ꢀ°Cꢀ(Tableꢀ3,ꢀentriesꢀ5ꢀandꢀ11–13).ꢀTheꢀconversionꢀofꢀ
POꢀ andꢀ yieldꢀ ofꢀ ethylꢀ 3‐hydroxybutyrateꢀ increasedꢀ withꢀ in‐
creasingꢀCOꢀpressureꢀandꢀchangedꢀslightlyꢀwhenꢀtheꢀCOꢀpres‐
sureꢀwasꢀgreaterꢀthanꢀ5ꢀMPaꢀ(Tableꢀ3,ꢀentriesꢀ12ꢀandꢀ14–16).ꢀInꢀ
addition,ꢀtheꢀeffectꢀofꢀtimeꢀonꢀthisꢀreactionꢀshouldꢀnotꢀbeꢀun‐
derestimatedꢀ (Tableꢀ 3,ꢀ entriesꢀ 16–18).ꢀ Theꢀ conversionꢀ ofꢀ POꢀ
andꢀyieldꢀofꢀethylꢀ3‐hydroxybutyrateꢀincreasedꢀwithꢀincreasingꢀ
time.ꢀFairlyꢀhighꢀconversionꢀ(99%)ꢀandꢀselectivityꢀ(98%)ꢀcouldꢀ
beꢀ obtainedꢀ withꢀ optimalꢀ andꢀ relativelyꢀ mildꢀ reactionꢀ condi‐
tionsꢀ(Tableꢀ3,ꢀentryꢀ19).ꢀ ꢀ
4
000
3500
3000
2500
2000
1500
1000
500
1
Wavenumber (cm )
Fig.ꢀ3.ꢀIRꢀspectraꢀofꢀ3a.ꢀ
3
.1.4.ꢀ ꢀ NMRꢀstudiesꢀ
Allꢀ fourꢀ saltsꢀ (3a–3d)ꢀ exhibitedꢀ similarꢀ Hꢀ andꢀ 13Cꢀ NMRꢀ
chemicalꢀshiftsꢀcomparedꢀwithꢀtheirꢀcorrespondingꢀhalideꢀpre‐
cursorsꢀ (2a–2d),ꢀ whichꢀ indicatedꢀ thatꢀ noꢀ majorꢀ changeꢀ oc‐
curredꢀ inꢀ theꢀ chemicalꢀ structureꢀ ofꢀ theꢀ cationicꢀ partꢀ ofꢀ theꢀ
compounds.ꢀThus,ꢀtheꢀcationicꢀpartꢀofꢀtheꢀcompoundsꢀwasꢀcon‐
1
1
firmedꢀtoꢀexhibitꢀtheꢀexpectedꢀstructure.ꢀInꢀtheꢀ HꢀNMRꢀspectra,ꢀ
theꢀpeaksꢀforꢀtheꢀ1‐HꢀofꢀtheꢀNꢀatomsꢀandꢀ1‐HꢀofꢀtheꢀN‐alkylsꢀ
wereꢀshiftedꢀupfieldꢀcomparedꢀwithꢀthoseꢀofꢀtheirꢀcorrespond‐
ingꢀ halideꢀ precursorsꢀ becauseꢀ ofꢀ theꢀ effectꢀ ofꢀ theꢀ interionicꢀ
hydrogenꢀ bonding.ꢀ Inꢀ addition,ꢀ theꢀ carbonylꢀ carbonꢀ atomsꢀ
wereꢀstillꢀnotꢀobservedꢀunderꢀnormalꢀconditions,ꢀasꢀpreviouslyꢀ
reportedꢀ[11,22],ꢀmostꢀlikelyꢀbecauseꢀofꢀtheꢀparamagnetismꢀofꢀ
theꢀcobaltꢀcenter.ꢀ ꢀ
3
.1.5.ꢀ ꢀ UV‐Visꢀstudiesꢀ
Theꢀ UV‐Visꢀ absorptionꢀ spectraꢀ forꢀ allꢀ fourꢀ compoundsꢀ
a–3dꢀ inꢀ theꢀ regionꢀ 200–700ꢀ nmꢀ wereꢀ investigatedꢀ inꢀ di‐
chloromethane.ꢀTheꢀresultsꢀareꢀpresentedꢀinꢀTableꢀ2.ꢀDataꢀforꢀ
KCo(CO)
ꢀ derivedꢀ fromꢀ theꢀ literatureꢀ [22]ꢀ areꢀ alsoꢀ listedꢀ forꢀ
3
4
comparison.ꢀTheꢀspectraꢀareꢀclearlyꢀsimilarꢀtoꢀthatꢀofꢀKCo(CO)4.
Accordingꢀ toꢀtheꢀliteratureꢀ[22],ꢀtheꢀlatterꢀ showsꢀaꢀmajorꢀ ab‐
ꢀ
sorptionꢀbandꢀatꢀ233ꢀnmꢀandꢀaꢀshoulderꢀatꢀ360ꢀnm,ꢀwhichꢀisꢀ
assignedꢀ asꢀ theꢀ internalꢀ charge‐transferꢀ absorptionꢀ bandꢀ (>ꢀ
Moreover,ꢀtheꢀcatalyticꢀperformanceꢀofꢀ3aꢀforꢀtheꢀhydroes‐
terificationꢀ ofꢀ POꢀ wasꢀ comparedꢀ withꢀ thatꢀ ofꢀ aꢀ conventionalꢀ
350ꢀnm).ꢀCompoundsꢀ3a–3dꢀexhibitꢀaꢀsimilarꢀabsorptionꢀbandꢀ
catalyticꢀsystemꢀCo
2
(CO)8ꢀ(Tableꢀ3,ꢀentryꢀ20).ꢀItꢀisꢀapparentꢀthatꢀ
atꢀapproximatelyꢀ230ꢀnm,ꢀasꢀobservedꢀinꢀTableꢀ2.ꢀTheꢀcharac‐
theꢀcatalyticꢀactivityꢀofꢀ3aꢀwasꢀbetterꢀthanꢀthatꢀofꢀCo
2
(CO) .ꢀTheꢀ
8

+ꢀ
teristicꢀ Co(CO)
presenceꢀofꢀCo(CO)
4
ꢀ bandꢀ atꢀ ∼230ꢀ nmꢀ persists,ꢀ indicatingꢀ theꢀ
existenceꢀofꢀ1,1‐dimethyl‐3,3‐diethylguanidinium appearedꢀtoꢀ
assistꢀ theꢀ ring‐openingꢀ processꢀ ofꢀ theꢀ POꢀ [23,28,30–32],ꢀ andꢀ
theꢀintroductionꢀofꢀtheꢀguanidiniumꢀILsꢀpatternꢀtoꢀtheꢀcatalystꢀ
notꢀ onlyꢀ preventedꢀ catalystꢀ leachingꢀ butꢀ alsoꢀ increasedꢀ theꢀ
stabilityꢀofꢀtheꢀcatalyst.ꢀ

4
.ꢀ ꢀ
3.1.6.ꢀ ꢀ HRMSꢀ(ESI)ꢀstudiesꢀ ꢀ
InꢀtheꢀHRMSꢀ(ESI)ꢀspectra,ꢀtheꢀpeaksꢀofꢀtheꢀcationsꢀandꢀani‐
onsꢀ areꢀ observed,ꢀ whichꢀ stronglyꢀ confirmsꢀ theꢀ structureꢀ andꢀ
purityꢀofꢀtheꢀexpectedꢀcompounds,ꢀexceptꢀthatꢀinꢀsomeꢀcases,ꢀ
theꢀcobaltꢀtetracarbonylꢀanionꢀtendsꢀtoꢀloseꢀoneꢀorꢀtwoꢀcarbon‐
3.2.2.ꢀ ꢀ Substrateꢀscopeꢀofꢀtheꢀterminalꢀepoxideꢀ
Theꢀreadyꢀalkoxycarbonylationꢀofꢀpropyleneꢀoxideꢀwithꢀcat‐
alystꢀ 3aꢀ inꢀ ethanolꢀ underꢀ relativelyꢀ mildꢀ reactionꢀ conditionsꢀ
motivatedꢀtheꢀstudyꢀofꢀtheꢀgeneralꢀrangeꢀofꢀthisꢀcatalyticꢀpro‐
cessꢀforꢀtheꢀsynthesisꢀofꢀβ‐hydroxyꢀesters.ꢀThus,ꢀtheꢀscopeꢀofꢀ
theꢀsubstrateꢀepoxidesꢀbearingꢀalkyl,ꢀalkenyl,ꢀglycidyl,ꢀheteroa‐
tom,ꢀaryl,ꢀandꢀalkyl‐arylꢀgroupsꢀforꢀtheꢀreactionꢀwasꢀexplored.ꢀ
Generally,ꢀβ‐hydroxyꢀestersꢀwereꢀobtainedꢀinꢀgoodꢀyields.ꢀTer‐
minalꢀepoxidesꢀbearingꢀsimpleꢀalkylꢀandꢀalkenylꢀgroupsꢀreactedꢀ
ylsꢀtoꢀaffordꢀCo(CO)
3
−ꢀorꢀCo(CO) −.ꢀ
2
3
1
.2.ꢀ ꢀ CatalyticꢀperformanceꢀofꢀcobaltꢀcarbonylꢀILsꢀbasedꢀonꢀ
,1,3,3‐tetra‐alkylguanidineꢀ
3.2.1.ꢀ ꢀ Optimizationꢀofꢀreactionꢀconditionsꢀ
Theꢀ catalyticꢀ activityꢀ ofꢀ cobaltꢀ carbonylꢀ ILsꢀ basedꢀ onꢀ

810ꢀ
WeiꢀZhangꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ805–812ꢀ
Tableꢀ3ꢀ
a
Optimizationꢀofꢀreactionꢀconditionsꢀ .ꢀ
OH
O
O
+
CO + EtOH
O
ꢀ
Conversionꢀ ꢀ ꢀ Selectivityꢀbꢀ
b
Catalyst/POꢀ ꢀ
o
Entryꢀ Catalystꢀ
Solventꢀ
T/ Cꢀ
P(CO)/MPa
t/hꢀ
(mol%)ꢀ
(%)ꢀ
54ꢀ
50ꢀ
46ꢀ
35ꢀ
77ꢀ
25ꢀ
27ꢀ
46ꢀ
92ꢀ
94ꢀ
14ꢀ
97ꢀ
99ꢀ
73ꢀ
82ꢀ
97ꢀ
35ꢀ
77ꢀ
99ꢀ
78ꢀ
(%)ꢀ
95ꢀ
91ꢀ
86ꢀ
85ꢀ
90ꢀ
80ꢀ
83ꢀ
85ꢀ
99ꢀ
97ꢀ
89ꢀ
95ꢀ
73ꢀ
90ꢀ
93ꢀ
96ꢀ
89ꢀ
98ꢀ
98ꢀ
85ꢀ
1
ꢀ
3aꢀ
3bꢀ
3cꢀ
3dꢀ
3aꢀ
3aꢀ
3aꢀ
3aꢀ
3aꢀ
3aꢀ
3aꢀ
3aꢀ
3aꢀ
3aꢀ
3aꢀ
3aꢀ
3aꢀ
3aꢀ
3aꢀ
2ꢀ
2ꢀ
2ꢀ
2ꢀ
2ꢀ
2ꢀ
2ꢀ
1ꢀ
3ꢀ
4ꢀ
2ꢀ
2ꢀ
2ꢀ
2ꢀ
2ꢀ
2ꢀ
EtOHꢀ(2ꢀmL)ꢀ
EtOHꢀ(2ꢀmL)ꢀ
EtOHꢀ(2ꢀmL)ꢀ
EtOHꢀ(2ꢀmL)ꢀ
EtOHꢀ(3ꢀmL)ꢀ
ꢀ 60ꢀ
ꢀ 60ꢀ
ꢀ 60ꢀ
ꢀ 60ꢀ
ꢀ 60ꢀ
ꢀ 60ꢀ
ꢀ 60ꢀ
ꢀ 60ꢀ
ꢀ 60ꢀ
ꢀ 60ꢀ
ꢀ 40ꢀ
ꢀ 80ꢀ
100ꢀ
ꢀ 80ꢀ
ꢀ 80ꢀ
ꢀ 80ꢀ
ꢀ 80ꢀ
ꢀ 80ꢀ
ꢀ 80ꢀ
ꢀ 80ꢀ
7ꢀ
7ꢀ
7ꢀ
7ꢀ
7ꢀ
7ꢀ
7ꢀ
7ꢀ
7ꢀ
7ꢀ
7ꢀ
7ꢀ
7ꢀ
4ꢀ
5ꢀ
6ꢀ
6ꢀ
6ꢀ
6ꢀ
6ꢀ
24ꢀ
24ꢀ
24ꢀ
24ꢀ
24ꢀ
24ꢀ
24ꢀ
24ꢀ
24ꢀ
24ꢀ
24ꢀ
24ꢀ
24ꢀ
24ꢀ
24ꢀ
24ꢀ
ꢀ 8ꢀ
16ꢀ
24ꢀ
24ꢀ
2
ꢀ
3
ꢀ
4
ꢀ
5
ꢀ
6
ꢀ
EtOHꢀ(0.5ꢀmL),ꢀ1,4‐dioxaneꢀ(2.5ꢀmL)ꢀ
EtOHꢀ(0.5ꢀmL),ꢀTHFꢀ(2.5ꢀmL)ꢀ
EtOHꢀ(3ꢀmL)ꢀ
7
ꢀ
8
ꢀ
9
ꢀ
EtOHꢀ(3ꢀmL)ꢀ
EtOHꢀ(3ꢀmL)ꢀ
EtOHꢀ(3ꢀmL)ꢀ
EtOHꢀ(3ꢀmL)ꢀ
EtOHꢀ(3ꢀmL)ꢀ
EtOHꢀ(3ꢀmL)ꢀ
EtOHꢀ(3ꢀmL)ꢀ
EtOHꢀ(3ꢀmL)ꢀ
EtOHꢀ(3ꢀmL)ꢀ
EtOHꢀ(3ꢀmL)ꢀ
EtOHꢀ(3ꢀmL)ꢀ
EtOHꢀ(3ꢀmL)ꢀ
1
1
1
1
1
1
1
1
1
1
2
0ꢀ
1ꢀ
2ꢀ
3ꢀ
4ꢀ
5ꢀ
6ꢀ
7ꢀ
8ꢀ
9ꢀ
0ꢀ
2ꢀ
2ꢀ
3ꢀ
3ꢀ
Co
2
(CO)
8
ꢀ
aꢀReactionꢀconditions:ꢀPOꢀ(5.0ꢀmmol).ꢀ DeterminedꢀbyꢀGCꢀwithꢀinternalꢀstandardꢀmethod.ꢀ
bꢀ
ꢀ
wellꢀ (Tableꢀ 4,ꢀ entriesꢀ 1–4).ꢀ Inꢀ addition,ꢀ variousꢀ glycidolꢀ
ether‐functionalizedꢀepoxidesꢀalsoꢀshowedꢀgoodꢀreactivityꢀ(Ta‐
bleꢀ 4,ꢀ entriesꢀ 5–7).ꢀ Moreover,ꢀ theꢀ epoxidesꢀ bearingꢀ heteroa‐
tomsꢀsuchꢀasꢀepichlorohydrinꢀobtainedꢀgeneralꢀyieldsꢀ(Tableꢀ4,ꢀ
entryꢀ8).ꢀInꢀaddition,ꢀaryl‐ꢀandꢀalkyl‐aryl‐functionalizedꢀepox‐
idesꢀ areꢀ knownꢀ toꢀ reactꢀ slowly,ꢀ thusꢀ affordingꢀ lowerꢀ yields.ꢀ
Fortunately,ꢀ 2‐phenylpropyleneꢀ oxideꢀ andꢀ 3‐phenylbuteneꢀ
However,ꢀtheꢀreactionꢀofꢀtheꢀcyclohexeneꢀoxideꢀfailedꢀtoꢀaffordꢀ
theꢀdesiredꢀisolatedꢀproductꢀbecauseꢀofꢀtheꢀpoorꢀreactivityꢀ(Ta‐
bleꢀ4,ꢀentryꢀ11).ꢀ ꢀ
3.2.3.ꢀ ꢀ EffectꢀofꢀconfigurationꢀonꢀethoxycarbonylationꢀofꢀPOꢀ
TheꢀeffectꢀofꢀtheꢀconfigurationꢀonꢀethoxycarbonylationꢀofꢀPOꢀ
wasꢀalsoꢀstudiedꢀ(Tableꢀ5)ꢀwithꢀthisꢀcatalyticꢀsystem.ꢀWeꢀob‐
servedꢀ thatꢀ theꢀ configurationꢀ ofꢀ theꢀ productꢀ wasꢀ consistentꢀ
withꢀtheꢀsubstrateꢀwithoutꢀracemization.ꢀ
1,2‐oxideꢀproducedꢀrelativelyꢀgoodꢀyieldsꢀcomparedꢀwithꢀthoseꢀ
reportedꢀinꢀpreviousꢀstudiesꢀ[25,39]ꢀ(Tableꢀ4,ꢀentriesꢀ9ꢀandꢀ10).ꢀ
Tableꢀ4ꢀ
a
Substrateꢀscopeꢀofꢀalkoxycarbonylationꢀofꢀterminalꢀepoxidesꢀtoꢀβ‐hydroxyꢀestersꢀ .ꢀ
O
OH
O
3a
+
CO
+
EtOH
R
R
O
ꢀ
Conver‐ Isolatedꢀ
sionꢀ (%) yieldꢀ(%)
Conver‐ Isolatedꢀ
sion (%) yieldꢀ(%)
Entryꢀ
Epoxideꢀ
Productꢀ
Entry
7ꢀ
Epoxideꢀ
Productꢀ
bꢀ
bꢀ
OH
O
O
OH
O
O
O
O
1ꢀ
99ꢀ
98ꢀ
95ꢀ
81ꢀ
90ꢀ
89ꢀ
O
89ꢀ
87ꢀ
53ꢀ
79ꢀ
70ꢀ
40ꢀ
ꢀ
O
ꢀ 4aꢀ
ꢀ 4bꢀ
O
O
4gꢀ
OH
O
OH
O
O
O
2ꢀ
8ꢀ
Cl
Cl
ꢀ
O
O
ꢀ 4hꢀ
O
OH
O
OH
OH
O
O
3ꢀ
9ꢀ
O
ꢀ
O
ꢀ 4cꢀ
4iꢀ
O
OH
O
O
O
4ꢀ
89ꢀ
97ꢀ
80ꢀ
92ꢀ
10ꢀ
11ꢀ
85ꢀ
14ꢀ
71ꢀ
0ꢀ
ꢀ
O
O
ꢀ 4dꢀ
ꢀ
O
ꢀ 4jꢀ
OH
OH
O
O
5ꢀ
O
O
O
O
ꢀ
O
ꢀ 4eꢀ
ꢀ
O
ꢀ
4kꢀ
O
OH
O
O
6ꢀ
O
91ꢀ
84ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
4fꢀ
ꢀ
aꢀ
ꢀ ꢀ
Reactionꢀconditions:ꢀepoxideꢀ(5.0ꢀmmol),ꢀ3aꢀ(0.15ꢀmmol)ꢀinꢀethanolꢀ(3.0ꢀmL)ꢀunderꢀCOꢀ6.0ꢀMPaꢀatꢀ80ꢀ°Cꢀforꢀ24ꢀh.
bꢀ
DeterminedꢀbyꢀGCꢀwithꢀinternalꢀstandardꢀmethod.ꢀ

ꢀ
WeiꢀZhangꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ805–812ꢀ
811ꢀ
2
016,ꢀ72,ꢀ3282–3287.ꢀ
Tableꢀ5ꢀ
a
[2] R.ꢀHayes,ꢀG.ꢀG.ꢀWarr,ꢀR.ꢀAtkin,ꢀChem.ꢀRev.,ꢀ2015,ꢀ115,ꢀ6357–6426.ꢀ
3] R.ꢀ Prado,ꢀ X.ꢀ Erdocia,ꢀ G.ꢀ F.ꢀ Deꢀ Gregorio,ꢀ J.ꢀ Labidi,ꢀ T.ꢀ Welton,ꢀ ACSꢀ
Sustain.ꢀChem.ꢀEng.,ꢀ2016,ꢀ4,ꢀ5277–5288.ꢀ
4] D.ꢀ R.ꢀ MacFarlane,ꢀ N.ꢀ Tachikawa,ꢀ M.ꢀ Forsyth,ꢀ J.ꢀ M.ꢀ Pringle,ꢀ P.ꢀ C.ꢀ
Howlett,ꢀG.ꢀD.ꢀElliott,ꢀJ.ꢀH.ꢀDavis,ꢀM.ꢀWatanabe,ꢀP.ꢀSimon,ꢀC.ꢀA.ꢀAn‐
gell,ꢀEnergyꢀEnviron.ꢀSci.,ꢀ2014,ꢀ7,ꢀ232–250.ꢀ
5] D.ꢀYang,ꢀD.ꢀL.ꢀWang,ꢀH.ꢀLiu,ꢀX.ꢀL.ꢀZhao,ꢀY.ꢀLu,ꢀS.ꢀJ.ꢀLai,ꢀY.ꢀLiu,ꢀChin.ꢀJ.ꢀ
Catal.,ꢀ2016,ꢀ37,ꢀ405–411.ꢀ
6] X.ꢀQ.ꢀXiong,ꢀC.ꢀYi,ꢀQ.ꢀHan,ꢀL.ꢀShi,ꢀS.ꢀZ.ꢀLi,ꢀChin.ꢀJ.ꢀCatal.,ꢀ2015,ꢀ36,ꢀ
EffectꢀofꢀconfigurationꢀonꢀethoxycarbonylationꢀofꢀPOꢀ .ꢀ
[
OH
O
O
3a
+
CO + EtOH
*
O
*
ꢀ
[
Conversionꢀbꢀ ꢀ
%)ꢀ
Selectivityꢀbꢀ ꢀ
eeꢀofꢀtheꢀ ꢀ
product ꢀ(%)ꢀ
—ꢀ
Opticalꢀ
ꢀ
c
(
(%)ꢀ
98ꢀ
Racꢀ(eeꢀ=ꢀ0)ꢀ
Sꢀ(>ꢀ99.9%)ꢀ
Rꢀ(>ꢀ99.9%)ꢀ
99ꢀ
99ꢀ
98ꢀ
[
[
[
[
99ꢀ
99ꢀ
>ꢀ99.9ꢀ
>ꢀ99.9ꢀ
aꢀReactionꢀconditions:ꢀPOꢀ(5.0ꢀmmol),ꢀ3aꢀ(0.15ꢀmmol)ꢀinꢀethanolꢀ(3.0ꢀ
mL)ꢀunderꢀCOꢀ6.0ꢀMPaꢀatꢀ80ꢀ°Cꢀforꢀ24ꢀh.
237–243.ꢀ
ꢀ
ꢀ ꢀ
7] S.ꢀ N.ꢀ Korade,ꢀ J.ꢀ D.ꢀ Patil,ꢀ D.ꢀ M.ꢀ Pore,ꢀ Monatsh.ꢀ Chem.,ꢀ 2016,ꢀ 147,ꢀ
2143–2149.ꢀ
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Organometallics,ꢀ2005,ꢀ24,ꢀ4039–4048.ꢀ
[9] P.ꢀJ.ꢀDyson,ꢀAppl.ꢀOrganometal.ꢀChem.,ꢀ2002,ꢀ16,ꢀ495–500.ꢀ
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J.ꢀPolin,ꢀJ.ꢀM.ꢀMcKenzie,ꢀH.ꢀG.ꢀRaubenheimer,ꢀDaltonꢀTrans.,ꢀ2003,ꢀ
b
ꢀ
DeterminedꢀbyꢀGCꢀwithꢀinternalꢀstandardꢀmethod.ꢀ ꢀ
cꢀDeterminedꢀbyꢀGCꢀwithꢀavailableꢀcapillaryꢀcolumnꢀChirasil‐DexꢀCB.ꢀ
ꢀ
Conversion
Selectivity
100
100
80
60
40
20
0
[
80
60
40
20
0
4
275–4281.ꢀ
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2
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2,ꢀ2122–2130.ꢀ
1
1
2
3
4
5
6
[
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Run
Fig.ꢀ 4.ꢀRecyclabilityꢀofꢀ3aꢀinꢀtheꢀalkoxycarbonylationꢀofꢀPO.ꢀReactionꢀ
conditions:ꢀPOꢀ(5.0ꢀmmol),ꢀ3aꢀ(0.15ꢀmmol)ꢀinꢀethanolꢀ(3.0ꢀmL)ꢀunder
COꢀ6.0ꢀMPaꢀatꢀ80ꢀ°Cꢀforꢀ24ꢀh.ꢀ
[
[
[
3.2.4.ꢀ ꢀ Catalystꢀreusabilityꢀ
[
19] Z.ꢀM.ꢀGuo,ꢀH.ꢀS.ꢀWang,ꢀZ.ꢀG.ꢀLv,ꢀZ.ꢀH.ꢀWang,ꢀT.ꢀNie,ꢀW.ꢀW.ꢀZhang,ꢀJ.ꢀ
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Organometal.ꢀChem.,ꢀ2011,ꢀ696,ꢀ3668–3672.ꢀ
ofꢀcatalystꢀ3aꢀwasꢀexaminedꢀforꢀtheꢀethoxycarbonylationꢀofꢀPO,ꢀ
andꢀtheꢀresultsꢀareꢀpresentedꢀinꢀFig.ꢀ4.ꢀTheꢀcatalystꢀ3aꢀcouldꢀbeꢀ
reusedꢀeffectivelyꢀatꢀleastꢀsixꢀtimesꢀwithꢀaꢀsmallꢀlossꢀofꢀselectiv‐
ityꢀandꢀonlyꢀaꢀminorꢀdecreaseꢀinꢀconversion.ꢀTheꢀcatalyticꢀsys‐
temꢀclearlyꢀexhibitedꢀgoodꢀrecyclability,ꢀwhichꢀisꢀconsideredꢀaꢀ
breakthroughꢀthatꢀcanꢀmostlyꢀbeꢀattributedꢀtoꢀtheꢀgoodꢀstabil‐
ityꢀofꢀtheꢀcatalyst.ꢀ ꢀ ꢀ
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[
[
[
[
4
3
4.ꢀ ꢀ Conclusionsꢀ
6
AꢀseriesꢀofꢀnewꢀcobaltꢀcarbonylꢀILsꢀbasedꢀonꢀ1,1,3,3‐tetra‐
ꢀ
25] S.ꢀ E.ꢀ Denmark,ꢀ M.ꢀ Ahmad,ꢀ J.ꢀ Organometal.ꢀ Chem.,ꢀ 2007,ꢀ 72,ꢀ
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characterizedꢀ usingꢀ variousꢀ techniques.ꢀ Becauseꢀ ofꢀ theꢀ pres‐
enceꢀofꢀinterionicꢀhydrogenꢀbonds,ꢀcompoundsꢀ3a–3dꢀareꢀrela‐
tivelyꢀ stableꢀ whenꢀ exposedꢀ toꢀ air.ꢀ Moreover,ꢀ theꢀ compoundsꢀ
exhibitedꢀremarkablyꢀgoodꢀthermalꢀstability.ꢀNotably,ꢀtheꢀcata‐
lystꢀ3aꢀexhibitedꢀquiteꢀgoodꢀcatalyticꢀactivityꢀandꢀreusabilityꢀinꢀ
theꢀ reactionꢀofꢀ alkoxycarbonylationꢀofꢀepoxides.ꢀTheꢀcatalyticꢀ
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