Selective hydrogenation of amides to alcohols in water solvent over a heterogeneous CeO2-supported Ru catalyst

Article abstract of DOI:10.1039/c8cc02697a

CeO₂-supported Ru (Ru/CeO₂) worked as an effective and reusable heterogeneous catalyst for the selective dissociation of the C-N bond in amides, particularly primary amides, with H₂ in water solvent at low reaction temperature of 333 K, and high yields of the corresponding alcohols were obtained from primary amides.

Full text of DOI:10.1039/c8cc02697a

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Marilyn M. Olmstead, Alan L. Balch, Josep M. Poblet, Luis Echegoyenet al.
Reactivity differences of Sc3N@C2n (2n 68 and 80). Synthesis of the
first methanofullerene derivatives of Sc N@D5h-C80
=
3
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DOI: 10.1039/C8CC02697A
Journal Namn
COMMUNICATIONU
Snlnctivn Hydrognnation of Amidns to Alcohols in Watnr Solvnnt
ovnr Hntnrognnnous CnO2-Supportnd Ru Catalyst
UMasazumiUTamura*USusumuUIshikawa,UMiiUBetchaku,UYoshinaoUNakagawa,UKeiichiUTomishige*U
ReceivedU00thUJanuaryU20xx,U
AcceptedU00thUJanuaryU20xxU
DOI:U10.1039/x0xx00000xU
www.rsc.org/
CnO2-suppontnd Ru (Ru/CnO2) worknd as an nffnctivn and rnusabln effective,Uhowever,UmostUofUtheseUcatalystsUrequiredUadditivesU
hntnrognnnous catalyst for snlnctivn dissociation of thn C-N bond in suchU asU strongU bases,U useU ofU organicU solvents,U andU highU
amidns, particularly primary amidns, with H2 in watnr solvnnt undnr temperatureU (typicallyU ≥353U K).U Moreover,U applicationU toU
low rnaction tnmpnraturn of 333 K, and high yinlds of thn primaryUamidesUisUcommonlyUdifficultUbecauseUofUtheUfreeUNHU
corrnsponding alcohols wnrn obtainnd from primary amidns.
bonds4a,UandUtheUyieldsUwereUveryUlowU(0~74%).URecently,USaitoU
andU co-workersU substantiatedU effectiveU transformationU ofU
benzamideUtoUbenzylUalcoholUinUhighUyieldUofU92%UbyUusingURuU
complexU ((P,(N,N)bpy,U P)Ru)7j,U althoughU theU catalystU systemU
requiredUhighUtemperatureU(433UK),UtolueneUsolventUandUstrongU
baseU(NaH).UWhenUourUmanuscriptUwasUsubmitted,UthereUareUnoU
reportsU onU heterogeneousU catalystsU developedU forU C-NU bondU
scissionUinUamides,UandUtheUreportedUhighestUyieldUfromUamidesU
toU alcoholsU overU heterogeneousU catalystsU isU veryU lowU (27%).U
DuringU theU reviewU ofU ourU manuscript,U outstandingU resultU onU
selectiveU hydrogenationU ofU C-NU bondsU inU amidesU overU
heterogeneousUAg/Al2O3UcatalystUwasUpublishedUbyUMilsteinUandU
co-workers10.UTheUcatalystUsystemUwasUeffectiveUforUsecondaryU
amidesUandUprovidedUhighUyieldUofUcorrespondingUalcoholsUandU
aminesU(upUtoU99%),UhoweverUsufferedUfromUuseUofUstrongUbasesU
suchUasUt-BuOK,UhighUtemperatureU(423UK),UuseUofUorganicUsolventU
(1,4-dioxane)U andU lowU yieldU fromU primaryU amidesU (61%).U
Therefore,U developmentU ofU effectiveU heterogeneousU catalystsU
forU reductiveU transformationU ofU amides,U particularlyU primaryU
amides,UtoUalcoholsUandUaminesUunderUmildUreactionUconditionsU
isUdesirable.UHerein,UweUfoundUthatURu/CeO2UwasUanUeffectiveU
heterogeneousUcatalystUforUselectiveUC-NUbondUdissociationUofU
amides,UparticularlyUprimaryUamides.UU
AmidesUareUubiquitousUinUnatureUasUpolypeptidesUofUproteinsUandU
canUbeUfoundUinUaUwideUrangeUofUchemicalsUsuchUasUpolyamidesU
(typicallyUnylons),UagrochemicalsUandUpharmaceuticalsUandUsoUon.U
ReductiveUtransformationUofUamidesUisUoneUofUimportantUorganicU
reactionsU [1],U andU thereU areU twoU pathwaysU (SchemeU 1):U (i)U
TransformationUofUamidesUtoUaminesUviaUdissociationUofUtheUC-OU
bond;U(ii)UTransformationUofUamidesUtoUalcoholsUandUaminesU(orU
ammonia)U viaU dissociationU ofU theU C-NU bond.U ReductionU
transformationU ofU amidesU isU generallyU difficultU dueU toU lowU
electrophilicityU ofU theU carbonylU carbonU inU amides2.U
Conventionally,UstoichiometricUreducingUagentsUsuchUasUmetalU
hydridesU areU usedU forU C-OU bondU scission,U andU
aminoborohydrides3UandUSmI2 UareUeffectiveUreducingUagentsUforU
4
C-NU bondU scissionU inU amides.U However,U theseU systemsU haveU
someUdrawbacksUsuchUasUhighUcostUofUreductantsUandUproductionU
ofU largeU amountU ofU salts.U AsU anU alternativeU method,U catalyticU
reductionUwithUcheapUreducingUagentsUsuchUasUH2UisUdesirable.U
VariousU homogeneous5U andU heterogeneous6U catalystsU haveU
beenUintensivelyUdevelopedUforUtheUrouteU(i).UAsUforUtheUrouteU(ii),U
variousURu7,UFe8UandUMn9UcomplexesUwereUreportedUtoUbeU
U
(i) Dissociation of C-O bond
(ii) Dissociation of C-N bond
R2
2 H2
R3
U
U
U
CatalyticU performanceU forU hydrogenationU ofU amidesU wasU
investigatedU byU hydrogenationU ofU cyclohexanecarboxamideU inU
waterUsolventUatU333UKUandU8UMPaUH2UasUaUmodelUreactionU(TableU
1).UNoUreactionUwasUobservedUinUtheUabsenceUofUcatalystsU(entryU
17).U AtU first,U variousU carbon-supportedU nobleU metalU catalystsU
wereUappliedUtoUtheUreactionU(entriesU1-4).URu/CUshowedUmuchU
higherUconversionUthanUtheUotherUcarbon-supportedUcatalysts,U
O
R2
R2
2 H2
R1
N
R1
N
+
HN
R1
OH
H2O +
R3
R3
Schnmn 1.UReductiveUtransformationUofUamides
U
a. Graduate School of Engineering, Tohoku University, Aoba 6-6-07, Aramaki, Aoba-
ku, Sendai, 980-8579 (Japan). Email: mtamura@erec.che.tohoku.ac.jp,
tomi@erec.che.tohoku.ac.jp
ElectronicUSupplementaryUInformationU(ESI)Uavailable:U[detailsUofUanyUsupplementary
informationUavailableUshouldUbeUincludedUhere].USeeUDOI:U10.1039/x0xx00000xU
ThisU workU wasU supportedU byU Grant-in-AidU forU ChallengingU Explora-toryU Research
(15K14219).U
andUtheUselectivityUtoUcyclohexanemethanolU(
whileURh/CUshowedUhighUselectivityUtoUcyclohexanemethylamineU
).UNext,UeffectUofUsupportsUinURuUcatalystsUwasUinvestigatedUbyU
1)UwasUhighU(90%),U
(
2
usingUvariousUmetalUoxideUsupportsU(TableU1,UentriesU5-11).UAllU
ThisUjournalUisU©UTheURoyalUSocietyUofUChemistryU20xx
J. Name.,U2013,U00,U1-3U|U1UU
PleaseUdoUnotUadjustUmarginsU

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COMMUNICATIONU
Journal NamnU
(a) UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU(b)U
Tabln 1.UHydrogenationUofUcyclohexanecarboxamideUoverUvariousUcatalystsU
CeO2
View Article Online
DOI: 10.1039/C8CC02697A
O
O
U
473 K
U
U
H2
(IV)
+
NH2
OH
NH2
OH
+
U
Catalyst
1
2
3
U
(III)
SelectivityU(%)U
U
EntryU
CatalystU
Conv.U(%)U
1
2
3
OthersU
3.1U
7.8U
23U
U
1U
2U
Ru/CaU
Rh/CaU
Pt/CaU
30U
3.5U
90U
29U
77U
28U
97U
99U
98U
96U
98U
98U
92U
56U
38U
42U
46U
U7.5U
63U
<0.1U
<0.1U
<0.1U
28U
(II)
U
U
U
(I)
70
3U
0.3U
0.3U
<0.1U
<0.1U
U0.2U
<0.1U
<0.1U
<0.1U
U1.4U
U0.0U
U7.6U
U1.5U
<0.1U
<0.1U
<0.1U
<0.1U
-U
4U
Pd/CaU
34U
200 300 400 500 600 700 800 900
Temperature /K
20
30
40
50
ο
60
2
θ
/
5U
Ru/CeO2U
Ru/SiO2U
Ru/ZrO2U
Ru/TiO2U
52U
U0.8U
0.2U
1.7U
3.3U
0.4U
0.7U
<0.1U
U4.3U
62U
2.0U
0.9U
0.9U
1.1U
0.8U
0.9U
0.5U
38U
(c)UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU(d)U
(D)
(C)
6U
40U
33U
27U
U
U
U
U
U
U
U
U
7U
8U
(B)
9U
Ru/SiO2-Al2O3U 22U
10U
11U
12U
13U
14U
15U
16U
17U
18U
16U
Ru/γ-Al2O3U
Ru/MgOU
Rh/CeO2U
Pt/CeO2U
Ir/CeO2U
Pd/CeO2U
CeO2U
(A)
U6.2U
U0.3U
U0.3U
U0.2U
U0.6U
<0.1U
<0.1U
<0.1U
<0.1U
<0.1U
-U
0
1
2
3
4
5
6
58U
Distance [10-1 nm]
54U
Figurn 1.UCharacterizationUofURu/CeO2Ucatalysts.U(a)UXRDUpatternsUofUCeO2UandU
Ru/CeO2UcatalystsU((I)UCeO2,U(II)URu/CeO2UafterUcalcination,U(III)URu/CeO2UafterU
reduction,U(IV)URu/CeO2UafterU24UhUreaction),U(b)UTPRUanalysisUofURu/CeO2.U(c)U
TEMUimageUofURu/CeO2UafterUreduction,U(d)UFourierUtransformUofUk3-weightedU
RuU K-edgeU EXAFSU analysesU ((A)U RuU powder,U (B)U RuO2,U (C)U Ru/CeO2U afterU
reduction,U(D)URu/CeO2UafterU48UhUreaction),UFTUrangeU30-120Unm-1.U
U
UU<0.1U
-U
>99U
-U
-U
ReactionUconditions:UcatalystU0.50UgU(metal:U4Uwt%)Ua0.4UgU(metal:U5Uwt%),U
cyclohexanecarboxamideU1.5Ummol,UwaterU20Uml,UH2U8UMPa,U333UK,U4Uh.U
OthersUincludeUcyclohexane,UmethylcyclohexaneUandUmethane.U
U
supportedURuUcatalystsUshowedUhighUselectivityUtoU1U(92-99%)U
speciesU(H/Ru=0.92),UsuggestingUthatURuUmetalUspeciesUareUhighlyU
dispersedUandUtheUparticleUsizeUofURuUmetalUspeciesUisUveryUsmall.U
TEMUimageUofURu/CeO2UprovidedUsmallURuUparticlesU(~1.5Unm)U
(FigureU1(c)),UandUmuchUsmallerUparticlesUwillUnotUbeUfoundUdueU
toUlowUcontrastUbetweenUCeO2UandURuUparticles.UXASUanalysesUofU
Ru/CeO2UcatalystsUafterUreductionUandUreactionUwereUcarriedUoutU
(FigureU1(d),UandUFiguresUS1UandUS2UandUTableUS2).URuUK-edgeU
XANESU spectraU ofU Ru/CeO2U catalystU areU similarU toU thatU ofU RuU
powderU(FigureUS1).UFourierUtransformUofUk3-weightedURuUK-edgeU
EXAFSUofURu/CeO2UshowedUtheUsignalUcorrespondingUtoURuUmetalU
(FigureU 1(d)),U andU theU curve-fittingU analysisU providedU theU
presenceUofURu-RuUbondUwithUaUcoordinationUnumberU(CN)UofU~5U
(FiguresUS1UandUS2,UandUTableUS2).UTheseUresultsUindicateUthatURuU
speciesU onU CeO2U wasU inU theU metallicU state,U whichU isU goodU
accordanceUwithUTPRUanalysis.UBasedUonUtheUCNUofURu-Ru,URuU
speciesUareUsubnanocluster11,UwhichUagreesUwithUtheUresultsUofU
XRD,UCO-adsorptionUandUTEMUanalyses.U
withU moderateU toU lowU conversionU (16-52%),U andU Ru/CeO2U
showedU higherU conversionU thanU theU otherU RuU catalysts.U OnlyU
CeO2U hadU almostU noU activityU forU theU reactionU (entryU 16).U
PerformanceU ofU CeO2-supportedU nobleU metalU catalystsU wasU
comparedUinUtheUsameUreactionU(TableU1,UentriesU5UandU12-15).U
TheU CeO2-supportedU nobleU metalU catalystsU exceptU Ru/CeO2U
showedUlowUconversionU(<U10%)UandUlowUselectivityUtoU1U(<U60%).U
AsUabove,UcombinationUofUCeO2UandURuUwasUtheUmostUeffectiveU
forU theU reaction.U TheU performanceU ofU Ru/CeO2U catalystsU withU
differentU RuU loadingU amountsU wasU comparedU inU theU sameU
reactionUwithUtheUsameURuUamountUbyUadjustingUtheUintroducedU
catalystU amountU (0.20U mmol,U TableU S1).U TheU conversionU
graduallyUincreasedUwithUincreasingUtheURuUloadingUamountUupU
toU 4U wt%,U andU theU conversionU graduallyU decreasedU withU
increasingURuUloadingUamountUmoreUthanU4Uwt%,UalthoughUtheU
differenceUofUtheUconversionsUisUnotUsoUlarge.UTheUselectivitiesUtoU
ReactionU parametersU suchU asU reactionU temperature,U H2U
pressure,U substrateU concentrationU andU solventU wereU
investigatedUinUtheUsameUreactionUwithURu/CeO2UcatalystU(TablesU
S3-S6).UEffectUofUreactionUtemperatureUwasUstudiedUatUtheUrangeU
fromU313UtoU413UKU(TableUS3).UTheUconversionUincreasedUwithU
increasingUtheUreactionUtemperature,Uhowever,UtheUselectivityUtoU
1
UwereUsimilarU(94-98%).UTherefore,U4Uwt%URuUsupportedUCeO2U
catalystUwasUselectedUasUanUoptimizedUone.U
Ru/CeO2U(Ru:U4Uwt%)UcatalystUwasUcharacterizedUbyUXRD,UTPR,U
TEMUandUXASU(FigureU1,UFiguresUS1UandUS2,UandUTableUS2).UXRDU
patternsUofURu/CeO2UcatalystsUafterUcalcination,UreductionUandU
reactionUareUalmostUtheUsameUasUthatUofUCeO2,UandUsignalsUdueUtoU
RuUspeciesU(RuUmetal:UmainUpeakU(101)UatU~44o,URuOx:UmainUpeakU
(101)UatU~35o)UwereUnotUdetectedU(FigureU1(a)),UwhichUimpliesU
thatURuUspeciesUareUhighlyUdispersed.UTPRUprofileUofURu/CeO2UisU
shownUinUFigureU1(b).UBasedUonUtheUreductionUtemperatureUofU
473UK,UtheUconsumedUH2UamountUbelowU473UKUisUcalculatedUtoUbeU
1.6Ummol/g.UConsideringUthatUtheUconsumedUH2UamountUisUmuchU
largerUthanURuUmetalUamountU(0.4Ummol/g,),URuUspeciesUonUCeO2U
isUreducedUtoURuUmetalUandUaUpartUofUCeO2UwasUalsoUreduced.UCOU
adsorptionUanalysisUconfirmedUhighUdispersionUofURuUmetalU
1UdrasticallyUdecreasedUatUhigherUtemperaturesUthanU333UK,UandU
thoseUtoUcyclohexanecarboxylicUacidU(3)UandUothersUincreased.UInU
termsU ofU activityU andU selectivity,U 333U KU wasU selectedU forU theU
followingUstudy.USolventsUoftenUaffectUtheUactivityUandUselectivity.U
TheUreactionsUwereUconductedUwithUvariousUpolarUsolventsUsuchU
asUwater,U1,2-dimethoxyethane,UTHF,U2-propanolUandUmethanolU
(TableUS4).UAmongUtheUsolventsUtested,UwaterUprovidedUhigherU
conversionUthanUtheUotherUsolvents,UalthoughUtheUselectivityUwasU
notUsoUdifferent.UTherefore,UwaterUwasUselectedUasUtheUbestUone.U
2U|UJ. Name.,U2012,U00,U1-3U
ThisUjournalUisU©UTheURoyalUSocietyUofUChemistryU20xxU
PleaseUdoUnotUadjustUmarginsU

Page 3 of 4
ChemComm
PleaseUdoUnotUadjustUmarginsU
Journal Namn
COMMUNICATION
100
80
60
40
20
0
Tabln 2.UHydrogenationUofUvariousUamidesUoverURu/CeO2UcataVlyieswtU Article Online
U
U
O
O
DOI: 10.1039/C8CC02697A
U
R3
R2
H2
Ru/CeO2
R3
R2
R1
Amine
N
R1
Alcohol
OH
+
+
+ Others
U
U
U
U
U
U
U
U
R1
Amide
N
R1
Carboxylic acid
OH
U
Conv.U
(%)U
C-basedUselectivityU(%)U
AlcoholU AmineU CarboxylicUacidU OthersU
EntryU
AmideU
O
U
1U
2U
3U
4U
UU82U
UU93U
UU85U
UU90U
92U
92U
91U
80U
<0.1U
<0.1U
<0.1U
<0.1U
7.8U
5.3U
6.4U
0.2U
2.9U
2.6U
0.9U
NH2
O
U
U
NH2
O
U
U
U
NH2
O
U
U
19U
NH2
U
0
10
20
Time /h
30
40
50
U
O
U
U
Figurn 2.UTime-courseUofUhydrogenationUofU1UoverURu/CeO2U(ꢀUconversion,UU
selectivityUtoU1,UꢁUselectivityUtoU2, ꢂUselectivityUtoU3, rUselectivityUtoUothers).U
ReactionU conditions:U Ru/CeO2U 0.5U gU (Ru:U 4U wt%,U 0.20U mmol),U
cyclohexanecarboxamideU1.5Ummol,UwaterU20Uml,UH2U8UMPa,U333UK.UOthersU
includeUcyclohexane,UmethylcyclohexaneUandUmethane.U
U
5U
6U
UU95U
UU98U
UU95U
>99U
97U
95U
99U
92U
<0.1U
<0.1U
<0.1U
<0.1U
3.5U
3.6U
1.3U
2.4U
<0.1U
1.5U
NH2
U
O
NH2
U
O
7U
<0.1U
UUU5.3bU
NH2
U
FromUtheUresultsUofUsubstrateUconcentrationUeffectU(TableUS5),U
higherU substrateU concentrationU providedU higherU conversion,U
althoughUtheUsolubilityUofUcyclohexanecarboxamideUwasUlimited.U
EffectUofUH2UpressureUwasUinvestigatedUatUtheUrangeUofU1-8UMPaU
(TableU S6).U TheU conversionU decreasedU withU decreasingU H2U
O
U
U
U
8aU
NH2
O
U
9aU
>99U
11U
<0.1U
<0.1U
0.2U
0.4U
88b,c
94b,c
U
N
H
U
pressure,UandUtheUselectivityUtoU
1
UalsoUgraduallyUdecreasedUwithU
U andU othersU
O
decreasingU H2U pressure,U andU selectivitiesU toU
3
10aU
>99U UUUUU5.1U
U
N
increased,UindicatingUthatUhighUH2UpressureUwasUpreferableUforU
theU reaction.U EnoughU conversionU andU highU selectivityU wereU
obtainedUevenUatUlowUH2UpressureUofU2UMPaU(34%UconversionUandU
92%UselectivityUatU4UhUandU333UK).U
U
ReactionUconditions:URu/CeO2U0.50Ug,UamideU1.5Ummol,UwaterU20Uml,UH2U8U
MPa,U333UK,U 48Uh.UOthersUincludeUcyclohexane,UmethylcyclohexaneU andU
methane.U aProductsU withU aU cyclohexaneU ring.U bOthersU areU mainlyU theU
benzeneUring-hydrogenatedUsubstrate.UcCH3NH2UorU(CH3)2NHUareUincluded.U
U
Time-courseU ofU hydrogenationU ofU cyclohexanecarboxamideU
overURu/CeO2UisUshownUinUFigureU2.UTheUconversionUincreasedU
withUtheUreactionUtimeUtoUreachUalmostU100%UconversionUatU48Uh.U
dissociationUofUtheUamideUgroupUtoUgiveUtheUalcoholsUandUtheU
correspondingUamountUofUCH3NH2UorU(CH3)2NH2,UalthoughUtheU
mainU productU isU theU benzeneU ring-hydrogenatedU substrateU
(entriesU 9U andU 10).U TheU reactivitiesU ofU secondaryU andU tertiaryU
amidesUwereUlowerUthanUthatUofUprimaryUamides,UandUthatUofUtheU
tertiaryUamideUwasUlowerUthanUthatUofUtheUsecondaryUamide.UTheU
tendencyUwillUbeUdueUtoUtheUstericUhindranceUofUtheUN-alkylUgroup.UU
ThereUareUtwoUpossibleUreactionUroutesUfromUamidesUtoUtheU
correspondingU alcoholsU (SchemeU 2)6e,7d:U (I)U reactionU routeU viaU
formationUofUcarboxylicUacidsU(hydrationUofUamidesUbyUwaterUtoU
carboxylicUacidsUandUsequentialUhydrogenationUofUtheUcarboxylicU
acidsUtoUalcohols).U(II)UreactionUrouteUviaUformationUofUaldehydesU
(hydrogenolysisU ofU amidesU toU aldehydesU orU hydrogenationU ofU
amidesU toU hemiaminalsU +U deammoniationU ofU hemiaminalsU toU
aldehydesUandUsequentialUhydrogenationU ofUtheUaldehydesUtoU
alcohols).U ToU clarifyU theU reactionU route,U variousU relatedU
substratesUwereUreactedUwithURu/CeO2Ucatalyst.UToUcheckUtheU
TheUselectivityUtoU
1
UwasUhighU(~95%)UatUanyUtime,UandUthatUtoU
3U
wasUalmostUconstantU(2~3%).UTheUyieldUofU
1
UreachedU93%UatU48Uh,U
whichUisUtheUhighestUyieldUamongUtheUreportedUonesUincludingU
homogeneousU catalyst-basedU systems.U TheU reusabilityU ofU
Ru/CeO2U wasU studiedU (FigureU S3).U Ru/CeO2U wasU reusedU threeU
timesU withoutU significantU lossU ofU activityU andU selectivity.U TheU
stateUofURuUmetalUspeciesUwasUnotUchangedUbeforeUandUafterUtheU
reactionUfromUXASUanalysesU(FigureU1(d),UFigureUS1UandUTableUS2),U
andUtheUstructureUofUCeO2UinURu/CeO2UwasUnotUchangedUfromUXRDU
analysisU(FigureU1(a)).ULeachedUamountUofURuUmetalUspeciesUwasU
analyzedU byU ICP-AES,U showingU thatU theU leachedU amountU wasU
belowUtheUdetectionUlimitUofUICP-AESU(<0.05%).UNoUcontributionU
ofUleachedUmetalUspeciesUwasUalsoUconfirmedUbyUleachingUtestU
(FigureUS4).UTheseUresultsUindicateUthatURu/CeO2UisUaUrobustUandU
reusableUheterogeneousUcatalyst.U
reactionUrouteU(I),UhydrogenationUofU 3UwasUcarriedUoutUatUtheU
TheUscopeUofUamidesUwasUinvestigatedUusingURu/CeO2UcatalystU
(TableU2).UVariousUlinearUalkylUprimaryUamidesUwereUconvertedUtoU
theUcorrespondingUalcoholsUinUhighUyieldUandUselectivityU(entriesU
1-4).U BranchedU alkylU primaryU amides,U isobutyramide,U
cyclohexanecarboxamideUandUpivalamide,UalsoUreactedUtoUgiveU
theUalcoholsUinUhighUyieldsU(entriesU5-7).UInUtheUcaseUofUbenzamide,U
aU primaryU amideU withU aU benzeneU ring,U selectiveU C-NU bondU
dissociationU ofU theU amideU groupU alsoU occurred,U althoughU theU
benzeneUringUwasUhydrogenatedUtoUcyclohexaneUringU(entryU8).U
SecondaryUandUtertiaryUamides,UN-methylUbenzamide,UandUN,N-U
dimethylUbenzamide,UalsoUunderwentUselectiveUC-NUbondU
sameU reactionU conditionsU asU thoseU inU hydrogenationU ofU
cyclohexanecarboxamideU (SchemeU 3(a)).U AfterU 24U h,U theU
conversionUwasU4.9%,UwhichUisUmuchUlowerUthanUthatUinUtheUcaseU
ofUhydrogenationUofU1U(90%),UindicatingUthatUtheUreactionUrouteU
(I)U isU notU dominant.U ThisU resultU isU supportedU byU theU factU thatU
hydrogenationUadequatelyUproceededUinUtheUsolventsUexceptUforU
waterU(TableUS4).UTherefore,UtheUreactionUrouteU(II)UwillUbeUmain.U
Next,U hydrogenationU ofU cyclohexanecarboxaldehydeU (
4)U wasU
conductedU(SchemeU3(b)).UHydrogenationUofU4UproceededUveryU
rapidly,U andU theU conversionU reachedU 96%U inU onlyU 5U minutes.U
ThisUjournalUisU©UTheURoyalUSocietyUofUChemistryU20xx
J. Name.,U2013,U00,U1-3U|U3U
PleaseUdoUnotUadjustUmarginsU

PleaseUdoUnotUadjustUmarginsU
ChemComm
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COMMUNICATIONU
Journal NamnU
4
5
(a)UM.USzostak,UM.USpain,UA.UJ.UEberhartUandUD.UJ.UProcter, J. Am.
Therefore,U theU reactionU rateU isU muchU higherU thanU thatU ofU
hydrogenationU ofU cyclohexanecarboxamideU (FigureU 2),U whichU
Chem. Soc.U2014,U136,U2268.U(b)US.UR.UHuq,US.UShVi,ieURw.AUDrtiicaleoOUanlnindeU
M.USzostak,UJ. Org. Chem.U2017,U82,U6528.UU
DOI: 10.1039/C8CC02697A
canU explainU noU observationU ofU
hydrogenationUofUcyclohexanecarboxamide.UInUaddition,U
reactedUoverURu/CeO2UcatalystUforU24UhU(SchemeU3(c)),UshowingU
lowU conversionU ofU U (1.4U %).U ThisU resultU indicatesU thatU theU
4
U inU theU time-courseU ofU
(a)U A.U A.U N.U Magro,U G.U R.U EasthamU andU D.UJ.U Cole-Hamilton,U
Chem. Commun.U 2007,U 3154.U (b)UJ.U Coetzee,U D.U L.U Dodds,UJ.U
Klankermayer,US.UBrosinski,UW.ULeitner,UA.UM.UZ.USlawinUandUD.U
J.U Cole-Hamilton,U Chem. Eur. J.U 2013,U 19,U 11039.U (c)U J.U R.U
Cabrero-Antonino,U E.U Alberico,U K.U Junge,U H.U JungeU andU M.U
1
UwasU
1
reactivityUofUalcoholsUisUveryUlowUunderUtheseUconditions,UleadingU
toUhighUalcoholUyieldsUinUhydrogenationUofUamides.UMoreover,U
Beller,UChem. Sci.U2016,U7,U3422.U(c)UT.UvomUStein,UM.UMeuresch,U
D.U Limper,U M.U Schmitz,U M.U Hölscher,U J.U Coetzee,U D.U J.U Cole-
Hamilton,UJ.UKlankermayerUandUW.ULeitner,UJ. Am. Chem. Soc.U
2014,U136,U13217.U(d)UM.UMeuresch,US.UWesthues,UW.ULeitnerU
andUJ.UKlankermayer,UAngew. Chem. Int. Ed.U2016,U55,U1392.U
(e)UM.-L.UYuan,UJ.-H.UXie,US.-F.UZhuUandUQ.-L.UZhou,UACS Catal.U
reactionUofU2UwasUconductedUwithURu/CeO2UforU4UhU(SchemeU3(d)).U
TheUconversionUwasUveryUlowU(5.6%)UcomparedUwithUtheUcaseUofU
cyclohexanecarboxamideU(TableU1,UentryU5),UandUtheUselectivityU
toUmethylcyclohexaneUwasUalsoUveryUlowU(2.7%),UsuggestingUthatU
contributionUofUdirectUhydrogenolysisUofUC-NUdissociationUisUlow.U
Therefore,U theU reactionU routeU (II)U willU beU mainU overU Ru/CeO2U
catalyst,UwhichUisUsimilarUtoUthatUproposedUbyUhomogeneousURuU
complexUcatalyst7d.U
2016,U
ChemCatChem,U2016,U
6
,U 3665.U (f)U M.-L.U Yuan,U J.-H.U XieU andU Q.-L.U Zhou,U
,U3036.U
8
6
(a)UB.UWojcik,UandUH.UAdkins,UJ. Am. Chem. Soc.U1934,U56,U2419.U
(b)UC.UHirosawa,UN.UWakasaUandUT.UFuchikami,UTetrahedron Lett.U
1996,U37,U6749.U(c)UG.UBeamson,UA.UJ.UPapworth,UC.UPhilipps,UA.U
M.U SmithU andU R.U Whyman,U J. Catal.U 2010,U 269,U 93.U (d)U G.U
Beamson,U A.U J.U Papworth,U C.U Philipps,U A.U M.U SmithU andU R.U
Whyman,UAdv. Synth. Catal.U2010,U352,U869.U(e)UG.UBeamson,U
A.UJ.UPapworth,UC.UPhilipps,UA.UM.USmithUandUR.UWhyman, J.
Catal.U 2011,U 278,U 228.U (f)U R.U Burch,U C.U Paun,U X.-M.U Cao,U P.U
Crawford,UP.UGoodrich,UC.UHardacre,UP.UHu,UL.UMcLaughlin,UJ.USáU
andUJ.UM.UThompson,UJ. Catal.U2011,U283,U89.U(g)UM.USteinUandU
B.U Breit,U Angew. Chem. Int. Ed.U 2013,U 52,U 2231.U (h)U Y.U
Nakagawa,U R.U Tamura,U M.U Tamura,U andU K.U Tomishige,U Sci.
Technol. Adv. Mater.U2015,U16,U014901.U(i)UJ.UCoetzee,UH.UG.U
Manyar,UC.UHardacreUandUD.UJ.UCole-Hamilton,UChemCatChemU
InU conclusion,U Ru/CeO2U wasU anU effectiveU andU reusableU
heterogeneousUcatalystUforUselectiveUhydrogenationUofUtheUC-NU
bondU inU amidesU withU H2U inU waterU solventU underU lowU reactionU
temperatureUofU333UK,UandUprimaryUamidesUwereUtransformedUtoU
theUcorrespondingUalcoholsUinUhighUyields.UU
U
Reaction route (I)
H2O
O
U
U
U
U
2 H2
-H2O
H2
O
R
OH
-R'-NH2
H2
R'
R
OH
R
N
H
R
O
-R'-NH2
Reaction route (II)
2013,U5,U2843.U(j)UK.-i.UShimizu,UW.UOnodera,UA.US.UTouchy,US.UM.U
A.UH.USiddiki,UT.UToyaoꢀUandUK.UKon,UChemistrySelectU2016,U
4,U
Schnmn 2.UTwoUpossibleUreactionUroutesUforUreductionUofUamidesUtoUalcoholsU
736.U(k)UT.UMitsudome,UK.UMiyagawa,UZ.UMaeno,UT.UMizugaki,UK.U
Jitsukawa,UJ.UYamasaki,UY.UKitagawa,UandUK.UKaneda,U Angew.
Chem. Int. Ed.U2017,U56,U9381.U
andUamines.U
U
O
Ru/CeO2
OH
U
U
U
U
U
U
U
U
U
+ H2O
(a)
(b)
OH
+ 2 H2
H2O 20 ml
24 h, 333 K
7
(a)UM.UIto,UA.USakaguchi,UC.UKobayashiUandUT.UIkariya,U J. Am.
Chem. Soc.U2007,U129,U290.U(b)UM.UIto,UL.UW.UKoo,UA.UHimizu,UC.U
Kobayashi,UA.USakaguchiUandUT.UIkariya,UAngew. Chem., Int. Ed.U
2009,U 48,U 1324.U (c)U M.U Ito,U C.U Kobayashi,U A.U HimizuU andU T.U
Ikariya,UJ. Am. Chem. Soc.U2010,U132,U11414.U(d)UE.UBalaraman,U
B.UGnanaprakasam,UL.UJ.UW.UShimonUandUD.UMilstein,U J. Am.
Chem. Soc.U2010,U132,U16756.U(e)UJ.UM.UJohn,US.UH.UBergens,U
Angew. Chem. Int. Ed.U2011,U50,U10377.U(f)UT.UMiura,UI.UE.UHeld,U
S.UOishi,UM.UNarutoUandUS.USaito,UTetrahedron Lett.U2013,U54,U
2674.U(g)UY.UKita,UT.UHiguchiUandUK.UMashima,UChem. Commun.U
2014,U 50,U 11211.U (h)U Cabrero-Antonino,U J.U R.;U Alberico,U E.;U
Drexler,UH.-J.;UBaumann,UW.;UJunge,UK.;UJungeUandUH.;UBeller,UM.U
3 (1.5 mmol) (8 MPa)
Conversion 4.9%, Selectivity 95%
OH
Ru/CeO2
O
+ H2
H2O 20 ml
5 min, 333 K
4 (1.5 mmol) (8 MPa)
Conversion 96%, Selectivity 91%
+ H2O
Ru/CeO2
(c)
OH
+ H2
H2O 20 ml
24 h, 333 K
1 (1.5 mmol) (8 MPa)
Conversion 1.4%, Selectivity <0.1%
Ru/CeO2
NH2
+ H2
(d)
+ NH3
H2O 20 ml
4 h, 333 K
2 (1.5 mmol) (8 MPa)
Conversion 5.6%, Selectivity 2.7%
Schnmn 3.UHydrogenationUofUmodelUsubstratesUoverURu/CeO2Ucatalyst.U(a)U3,U
(b)UcyclohexanecarbaldehydeU(4),U(c)U1,U(d)U2.U
ACS Catal.U2016,U6,U47.U(i)UL.URasu,UJ.UM.UJohn,UE.UStephenson,UR.U
Endean,US.UKalapugama,UR.UClément,UandUS.UH.UBergens,UJ. Am.
Chem. Soc.U2017,U139,U3065.U(j)UT.UMiura,UM.UNaruto,UK.UToda,U
Rnfnrnncns
T.UShimomuraUandUS.USaito,USci. Rep.U2017,U
Y.U Li,U Q.-b.U Liu,U G.U A.U Solan,U Y.U Ma,U andU W.-H.U Sun,U
ChemCatChemU2017, ,U4275.U(l)UL.UShi,UX.UTan,UJ.ULong,UX.UXiong,U
S.UYang,UP.UXue,UH.ULvUandUX.UZha,UChem. Eur. J.U2017,U23,U546.U
(a)UJ.UA.UGarg,US.UChakraborty,UY.UBen-DavidUandUD.UMilstein,
Chem. Commun.U 2016,U 52,U 5285.U (b)U N.U M.U Rezayee,U D.U C.U
7,U1586.U(k)UZ.UWang,U
1
D.UJ.UC.UConstable,UP.UJ.UDunn,UJ.UD.UHayler,UG.UR.UHumphrey,UJ.UL.U
Leazer,U Jr.,U R.U J.U Linderman,U K.U Lorenz,U J.U Manley,U B.U A.U
Pearlman,UA.UWells,UA.UZakshUandUT.UY.UZhang,U Green Chem.U
9
8
9
2007,U
(a)UP.UA.UDubUandUT.UIkariya,UACS Catal. 2012,U
9,U411.U
2
2
,U1718.U(b)UA.UM.U
Samblanet,UandUM.US.USanford,UACS Catal.U2016,U6,U6377.U(c)UU.U
Smith,UR.UWhyman,UChem. Rev.U2014,U114,U5477.U(c)UA.UVolkov,U
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ThisUjournalUisU©UTheURoyalUSocietyUofUChemistryU20xxU
PleaseUdoUnotUadjustUmarginsU