Speaker : Po-Yuan Chung Supervisor : Prof. Shuchun Joyce Yu Date : 2008/06/16
1 Recyclable Organomolybdenum Lewis Acid Catalyst and Microwave Assisted Pechmann Condensation...
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Recyclable Organomolybdenum LewiRecyclable Organomolybdenum Lewis Acid Catalyst and Microwave Assistes Acid Catalyst and Microwave Assisted Pechmann Condensation Reactionsd Pechmann Condensation Reactions
Student : Chia-Pei Chung Supervisor : Prof. Shuchun Joyce Yu
2006 / 07 / 20Department of Chemistry & Biochemistry
Chung Cheng University
2
Pechmann CondensationPechmann CondensationPechmann CondensationPechmann Condensation
The Pechmann condensation is a synthesis of coumarins, starting from a phenol and a ester or carboxylic acid containing a β-carbonyl group.
Coumarin synthesis
Woodruff, E. H. Organic Syntheses, 1944, 24, 69.Pechmann, H. V.; Duisberg, C. Ber. 1883, 16, 2119.
OH
OEt
OO O O
+2 eq. AlCl3, PhNO2
100 ~ 130 oC4 h
Phenol Ethyl acetoacetate 80%
3
CoumarinsCoumarinsCoumarinsCoumarins
present in seeds, root, and leaves of many plant species
As additives to food and cosmetics, optical brightening agents, and dispersed fluorescent and laser dyes
has clinical value as the precursor for several anticoagulants, antibacterial, anticancer
can be synthesized by one of such methods as the Claisen rearrangement, Perkin reaction, Knoevenagel condensation, Reformatsky reaction, Wittig reactions, as well as the Pechmann Condensation reaction
1
2
345
6
7
88a O
4a
O
benzo-2-pyrone
4
Acidic Catalysts for Pechmann CondensationAcidic Catalysts for Pechmann Condensation
Proton Donor Brønsted AcidsProton Donor Brønsted Acids
H2SO4, HCl, TFA (trifluoroacetic acid)
Pechmann V. H.; Duisberg C. Chem. Ber. 1884, 17, 929.
Woods, L. L.; Sapp, J. J. Org. Chem. 1962, 27, 3703.
Traditional Lewis Acid CatalystsTraditional Lewis Acid Catalysts
InCl3, AlCl3, BiCl3, FeCl3, TiCl4, ZrCl4, P2O5, PCl3, POCl3
Bose, D. S.; Rudradas, A. P.; Babu, M. H. Tetrahedron Lett. 2002, 43, 9195.
S. K. De, R. A. Gibbs, Synthesis, 2005, 1231.
Simmonis, H.; Remmert, P. Chem. Ber. 1914, 47, 2229.
Robertson, A.; Sandrock, W. F.; Henry, C. B. J. Chem. Soc. 1931, 2426.
5
Acidic Catalysts for Acidic Catalysts for Pechmann Condensation -- continued Pechmann Condensation -- continued
Lanthanide Lewis Acid CatalystsLanthanide Lewis Acid Catalysts
Yb(III), Sm(III) Fillion, E. et. al. J. Org. Chem. 2006, 71, 409.
Bahekar, S. S.; Shinde, D. B. Tetrahedron Lett. 2004, 45, 7999.
OthersOthers
graphite / montmorillonite K10
Amberlyst-15, Nafion
Heteropoly acid (H6P2W18O62 . 24H2O)
Fre`re, S.; Thie´ry, V.; Besson, T. Tetrahedron Lett. 2001, 42, 2791.
Sabou, R.; Hoelderich, W. F.; Ramprasad, D.; Weinand, R. J. Catal. 2005, 232, 34.
Laufer, M. C.; Hausmann, H.; Hölderich, W. F. J. Catal. 2003, 218, 315.
Autino, J. C. et. al. Tetrahedron Lett. 2004, 45, 8935.
6
TFA Catalyzed Pechmann CondensationTFA Catalyzed Pechmann CondensationTFA Catalyzed Pechmann CondensationTFA Catalyzed Pechmann Condensation
OH
R OEt
O OO O
R
+
TFA3.5 e.q.
reflux0.25 ~ 20 h
phenol £]-carbonyl ester 30% ~100%
Woods, L. L.; Sapp, J. J. Org. Chem. 1962, 27, 3703.
Phenol used: Phloroglucinol, 2-Methylresorcinol, Resorcinol, Orcinol, 4-Chlororesorcinol, Pyrogallol, 3-Hydroxydiphenyl amine
β-carbonyl esters used: Ethyl benzoyl acetate
7
Indium(III) Chloride Catalyzed Indium(III) Chloride Catalyzed Pechmann CondensationPechmann Condensation
Indium(III) Chloride Catalyzed Indium(III) Chloride Catalyzed Pechmann CondensationPechmann Condensation
OH
R OEt
O OO O
R+
InCl3(10 mol%)
65 ~ 130 oC30 ~ 240 min
phenol ethyl acetoacetate 55% ~ 98%
Bose, D. S.; Rudradas, A. P.; Babu, M. H. Tetrahedron Lett. 2002, 43, 9195.
Phenol used: Resorcinol, Orcinol, 4-, Pyrogallol, 3-Hydroxydiphenyl amine, 3-methoxyphenol, 1,3,5-trihydroxybenzene, phenol, 1-naphthol
8
POClPOCl33 Catalyzed Pechmann Condensation Catalyzed Pechmann Condensation in Neutral Ionic Liquids in Neutral Ionic Liquids
POClPOCl33 Catalyzed Pechmann Condensation Catalyzed Pechmann Condensation in Neutral Ionic Liquids in Neutral Ionic Liquids
OH
ROEt
O O O O
R+
POCl3(30 mol%)
[bmim]PF6
30 ~ 100 oC, 40 ~ 60 minphenol ethyl acetoacetate 47% ~ 95%
Potdar, M. K.; Rasalkar, M. S.; Mohile, S. S.; Salunkhe, M. M. J. Mol. Catal. A Chem. 2005, 235, 249.
Phenol used: Resorcinol, 2-Methylresorcinol, Orcinol, Pyrogallol, 1,3,5-trihydroxybenzene, 2',4'-Dihydroxyacetophenone
9
Yb(OTf)Yb(OTf)3 3 Catalyzed Pechmann Condens Catalyzed Pechmann Condensationation
Yb(OTf)Yb(OTf)3 3 Catalyzed Pechmann Condens Catalyzed Pechmann Condensationation
OHR
O OR+
O
O
O
O
H
OMeYb(OTf)3
(10 mol%)
CH3NO2
100oC, 1.5h 31% ~ 88%
Fillion, E. et. al. J. Org. Chem. 2006, 71, 409.
Phenol used: 3,5-dimethoxyphenol, 3,4-dimethoxyphenol, sesamol, 3-methoxy-2-methylphenol
10
Microwave acceleration of the Pechmann reacMicrowave acceleration of the Pechmann reaction on graphite/montmorillonite K10tion on graphite/montmorillonite K10
Microwave acceleration of the Pechmann reacMicrowave acceleration of the Pechmann reaction on graphite/montmorillonite K10tion on graphite/montmorillonite K10
H2N OHH3CO
OCH3
OO
O OH2N
COOCH3
O
130oC+
Experimental Experimental conditionsconditions
Conventional heatingConventional heating Microwave irradiationMicrowave irradiation
Reaction Reaction time (min)time (min)
YieldYield
(%)(%)Reaction Reaction
time (min)time (min)YieldYield
(%)(%)
Neat (fusion)Neat (fusion) 120120 3636 8585 3939
Support: graphiteSupport: graphite 120120 4444 5050 4444
Support: Support:
graphite:K10 (2:1)graphite:K10 (2:1)a, a,
bb
6666 6464 3030 6666
a. No modifications were observed when a preliminary activation (2 h at 180°C) of the clay was realized.
b. No significant results were observed in the absence of graphite (montmorillonite K10 + phenol + b-ketoester).
Fre`re, S.; Thie´ry, V.; Besson, T. Tetrahedron Lett. 2001, 42, 2791.
11
Wells–Dawson heteropolyacid Catalyzed Wells–Dawson heteropolyacid Catalyzed Pechmann Condensation Pechmann Condensation
Wells–Dawson heteropolyacid Catalyzed Wells–Dawson heteropolyacid Catalyzed Pechmann Condensation Pechmann Condensation
+OH
R H3CCOOEt
X
OO O
CH3
X
R
X = H, CH3
H6P2W18O62¡D24H2O
toluene, refluxor
sovent-free, 130oC
1 mol%
38% ~ 97%
Romanelli,G. P.; Bennardi, D.; Ruiz, D. M.; Baronetti, G.; Thomas, H. J.; Autino, J. C.Tetrahedron Lett. 2004, 45, 8935.
Phenol used: resorcinol, phloroglucinol, 3-methoxyphenol, pyrogallol, 3,4-dimethylphenol, 3-methylphenol, orcinol, 1-naphthol
12
Synthesis of Coumarins by Grubbs’ Synthesis of Coumarins by Grubbs’ CatalystCatalyst
Synthesis of Coumarins by Grubbs’ Synthesis of Coumarins by Grubbs’ CatalystCatalyst
Ph
N N
PCy3
Cl
ClRu
MeMe
Grubbs' catalystVan, T. N.; Debenedetti, S.; Kimpe, N. D. Tetrah
edron Lett. 2003, 44, 4199.
O
O
O
O5 mol% Grubbs' catalyst
CH2Cl2, reflux, 24 h
70%
13
DDisadvantagesisadvantages of Brønsted Acids of Brønsted AcidsDDisadvantagesisadvantages of Brønsted Acids of Brønsted Acids
Proton Donor Brønsted AcidsProton Donor Brønsted Acids
– Catalysts have to be used in excess, for example sulfuric acid, 10–12 equiv, trifluoroacetic acid, 3–4 equiv.
– Longer reaction time and very often temperatures to be excess 150 oC and above.
– Their corrosive nature and the formation of several side products make them difficult to handle.
– The disposal of acidic waste leads to environmental pollution.
14
DDisadvantagesisadvantages of Traditional and of Traditional and Lanthanide Lewis Acid Lanthanide Lewis Acid
DDisadvantagesisadvantages of Traditional and of Traditional and Lanthanide Lewis Acid Lanthanide Lewis Acid
Traditional Lewis Acid CatalystsTraditional Lewis Acid Catalysts– Many chlorinated derivatives are highly moisture sensitive
and hydrolyse rapidly under conventional storage or standard reaction conditions.
– The disposal of acidic waste leads to environmental pollution.
– Can not control electronic and steric environments around metal Lewis acid center.
Lanthanide Lewis Acid CatalystsLanthanide Lewis Acid Catalysts– Lanthanide metals are relatively rare.
15
MotivationMotivationMotivationMotivation
Low Oxidation State Transition MetalsLow Oxidation State Transition Metals– Relatively high moisture – and oxygen – stability – Inexpensive– Tunable electronic and steric environments around metal ce
nter
GreenGreen ChemistryChemistry– Greener solvents
R.T. ionic liquids, [Bmim]PF6
– Energy saving Catalysis under microwave flash heating replace thermal heating– Recyclable catalyst
16
Preparation of Organomolybdenum CatalystPreparation of Organomolybdenum CatalystPreparation of Organomolybdenum CatalystPreparation of Organomolybdenum Catalyst
Thermal Thermal conditionsconditions
N NN
Mo
OCCOOC
P
O
2 eq NOBF4
0oC / stir 1 hr NN
N
Mo
ONNOOC
P
O2+
(BF4-)2
dry CH3NO2
75% yield
NN
N
N NN
Mo
OCCOOC
P
O
reflux (82oC) / 18 hrdry CH3CN
MoCO
COCO
COOC
OCP
O
80% yield
17
Crotonaldehyde-Lewis Acid AdductCrotonaldehyde-Lewis Acid AdductCrotonaldehyde-Lewis Acid AdductCrotonaldehyde-Lewis Acid Adduct
H3
O
H2
O
H3
L.A.O
L.A.
H1
H2
CH34
L.A.
H3
CH34
H1 H1
H2
CH34
H2
O
H3
CH34
H1
L.A.
CH34
H3
H2
H1O
L.A.
H3
CH34
H2
H1 OL.A.
11H chemical shiftH chemical shift HH11 H H22 HH33 H H44
crotonaldehydecrotonaldehyde
crotonaldehyde + crotonaldehyde + Cat.Cat.
9.41 6.08 7.01 9.41 6.08 7.01 2.032.03
9.89 6.71 8.14 9.89 6.71 8.14 2.322.32
Chemical shift diff.Chemical shift diff. 0.48 0.63 0.48 0.63 1.131.13 0.290.29
Childs, R. F. et. al. Can. J. Chem. 1982, 60, 801.
18
Lewis acid △δ on H3 (ppm)BBr3 1.49
AlCl3 1.23
[OP(2-Py)3W(CO)(NO)2](SbF6)2 1.23
[OP(2-Py)3W(CO)(NO)2](BF4)2 1.22
[P(2-Py)3W(CO)(NO)2](SbF6)2 1.21
[HOC(2-Py)3W(CO)(NO)2](SbF6)2 1.19
[P(2-Py)3W(CO)(NO)2](BF4)2 1.18
BF3 1.17
AlEtCl2 1.15
[OP(2-Py)3Mo(CO)(NO)2](BF4)2 1.13
[HC(2-Py)3Mo(CO)(NO)2](SbF6)2 1.05
TiCl4 1.03
[P(2-Py)3Mo(CO)(NO)2](BF4)2 0.99
[Me3P(CO)3(NO)W]+ 0.93
SnCl4 0.87
[CpMo(CO)2]+(PF6) 0.70
Et3Al 0.63
[CpFe(CO)2]+BF4 0.54
19
Spectral Data of CO Coordinated Spectral Data of CO Coordinated CatalystsCatalysts
Spectral Data of CO Coordinated Spectral Data of CO Coordinated CatalystsCatalysts
Organometalliccompound
chemical shift
(13C NMR)
IR absorption band
[OP(2-py)3W(CO)(NO)2](BF4)2 190.5 ppm 2156 cm-1/ nujol
[P(2-py)3W(CO)(NO)2](SbF6)2 192.0 ppm 2143 cm-1/ nujol
[P(2-py)3W(CO)(NO)2](BF4)2 192.2 ppm 2148 cm-1/KBr
Vapor CO 2143 cm-1
Mo(CO)6 202.3 ppm 2115,1983 cm-1/nujol
W(CO)6 192.1 ppm 2110,1980 cm-1/KBr
[OP(2-py)3Mo(CO)(NO)2](BF4)2 223.0 ppm 2060 cm-1/KBr
[P(2-py)3Mo(CO)(NO)2](BF4)2 222.0 ppm 2046cm-1/KBr
OP(2-py)3Mo(CO)3 227.5 ppm 1910,1806 cm-1/nujol
P(2-py)3Mo(CO)3 227.3 ppm 1908,1797cm-1/CD3Cl
OP(2-py)3W(CO)3 222.1 ppm 1890 cm-1/ nujol
P(2-py)3W(CO)3 222.9 ppm 1880,1762 cm-1/KBr
20
Organomolybdenum Lewis Acid Catalyzed Organomolybdenum Lewis Acid Catalyzed Pechmann Condensation Pechmann Condensation
Organomolybdenum Lewis Acid Catalyzed Organomolybdenum Lewis Acid Catalyzed Pechmann Condensation Pechmann Condensation
Thermal Thermal conditionsconditionsOH
ROEt
O O O O
R+
phenol ethyl acetoacetate
[O=P(2-py)3Mo(CO)(NO)2](BF4)21 mol%
120 oC, neat or 0.5 ml solvent
Solvent system: [bmim]PF6 or CH3CN or DMF or CH3NO2 or THF
OHHO
OHO
OHHO
OHOHHO
OHHOOH
HO OH
OH
OH
NO2 OH
O2N
Phenol
Resorcinol 1,3,5-trihydroxybenzene
3-methoxyphenol
Orcinol2-methylresorcinol
2-nitrophenol 4-nitrophenol
1-naphthol
Pyrogallol
O O
OHO
OHO H2N OH
3,5-dimethoxyphenol 3-aminophenolsesamol
OH
21
Ionic LiquidsIonic LiquidsIonic LiquidsIonic Liquids
Seddon, K. R. et. al. Pure Appl. Chem. 2000, 72, 2275.
22
Coordinative Characteristics of Various Coordinative Characteristics of Various Anions Anions
Coordinative Characteristics of Various Coordinative Characteristics of Various Anions Anions
Wasserscheid, P., et. al. Angew. Chem. Int. Ed. 2000, 39, 3772.
Cl-
AcO-
NO3-
SbF6-
BF4-
PF6-
Al2Cl7-
Al3Cl10-AlCl4
-
CuCl2-
basic/ stronglycoordinating
neutral/ weakly coordinating
acidic/non- coordinating
acidic/ coordination
SO42- Cu2Cl3
-
Cu3Cl4-
23
Room temperature ionic liquids exhibit many properties which make them potentially attractive media for homogeneous catalysis:
They have essentially no vapour pressure. They generally have reasonable thermal stabili
ty. They are able to dissolve a wide range of organi
c, inorganic and organometallic compounds. The solubility of gases. They are immiscible with some organic solvent
s. Ionic liquids have been referred to as ‘designe
r solvents’ by a suitable choice of cation / anion.
24
OH
ROEt
O O O O
R+
phenol ethyl acetoacetate120 oC, 48 h, neat
no catalyst
Entry PhenolYield (%)
Entry PhenolYield (%)
Entry PhenolYield (%)
1 n. d. 6 n. d. 11 n. d.
2 n. d. 7 n. d. 12 n. d.
3 n. d. 8 n. d. 13 n. d.
4 n. d. 9 n. d.
5 n. d. 10 n. d.
O O
OH
O
OHO
OHHO
OH
HO OH
OHO
OHHO
OH
OHHO
OH
NO2
OHHO
OH
OH
O2N
OH
H2N OH
25
OH
ROEt
O OO O
R+
phenol ethyl acetoacetate
[O=P(2-py)3Mo(CO)(NO)2](BF4)21 mol%
120 oC, neat
Entry Phenol TimeYield (%)
Entry PhenolTime(h)
Yield (%)
1 1 h 98 8 10 h 82
225min
80 9 4 h 84
315min
75 10 24 h 81
415min
69 11 24 h n. d.
5 4 h 69 12 24 h n. d.
6 10 h 93 13 24 h n. d.
7 5 h 91
OHHO
OH
HO OH
OHHO
OHHO
OHHO
OH
O O
OH
O
OHO
OHO
OH
H2N OH
OH
NO2
OH
O2N
OH
26
OH
ROEt
O OO O
R+
phenol ethyl acetoacetate
[O=P(2-py)3Mo(CO)(NO)2](BF4)21 mol%
120 oC, 0.5 ml solvent
Entry Phenol Time
Yield (%)
[Bmim]PF6
CH3NO2 THF CH3CN DMF
1 1 h 91 64 32 9 n. d.
2 24 h -- 86 54 24 3
325min
84
(20 min)12 5 4 n. d.
4 7 h -- 8242
(68)*40
(69)*n. d.(5)*
515min
82
(10 min)19 12 13 n. d.
6 2 h -- 83 81 8212
(79)*
OHHO
OH
HO OH
OHHO
OH
*After reacting 24 h, the products’ yield
27
OH
ROEt
O OO O
R+
phenol ethyl acetoacetate
[O=P(2-py)3Mo(CO)(NO)2](BF4)21 mol%
120 oC, 0.5 ml solvent
Entry Phenol TimeYield (%)
[Bmim]PF6
CH3NO2 THF CH3CN DMF
715min
84 21 18 16 n. d.
8 2 h -- 82 80 80n. d.
(5)*
9 4 h82
(20 min)22 10 n. d. n. d.
10 24 h -- 60 26 5 n. d.
OHHO
OHHO
*After reacting 24 h, the products’ yield
28
OH
ROEt
O OO O
R+
phenol ethyl acetoacetate
[O=P(2-py)3Mo(CO)(NO)2](BF4)21 mol%
120 oC, 0.5 ml solvent
Entry Phenol TimeYield (%)
[Bmim]PF6
CH3NO2 THF CH3CN DMF
11 10 h92
(6 h)31 21 6 n. d.
12 24 h -- 54 40 12 n. d.
13 5 h93
(1 h)43 14 11 n. d.
14 24 h -- 82 68 52 15
15 10 h88
(5 h)18 10 11 n. d.
16 24 h -- 34 24 28 n. d.
O O
OH
O
OHO
OHO
29
OH
ROEt
O OO O
R+
phenol ethyl acetoacetate
[O=P(2-py)3Mo(CO)(NO)2](BF4)21 mol%
120 oC, 0.5 ml solvent
Entry Phenol TimeYield (%)
[Bmim]PF6
CH3NO2 THF CH3CN DMF
17 4 h92
(2 h)75 64 65 61
18 6 h -- 92 88 90 77
19 8 h -- -- -- -- 82
20 10 h 88 16 10 5 n. d.
21 24 h -- 38 23 14 n. d.
OH
H2N OH
30
OH
ROEt
O OO O
R+
phenol ethyl acetoacetate
[O=P(2-py)3Mo(CO)(NO)2](BF4)21 mol%
120 oC, 0.5 ml solvent
Entry Phenol Time
Yield (%)
[Bmim]PF6
CH3NO2 THF CH3CN DMF
22 24 h n. d. n. d. n. d. n. d. n. d.
23 24 h n. d. n. d. n. d. n. d. n. d.
24 24 h n. d. n. d. n. d. n. d. n. d.
OH
NO2
OH
O2N
OH
31
Entry
Phenol
Yield (%)Entr
yPhenol
Yield (%)
neat[Bmim]PF
6neat
[Bmim]PF6
1 98(1 h)
91 (1 h)
69 (20 min)8
82(10 h)
88
(5 h)
2 80(25 min)
84(20 min) 9
84(4 h)
92
(2 h)
375
(15 min)82
(10 min) 1081
(24h)88
(10 h)
4 69(15 min)
84(15 min) 11 n. d.
(24 h)n. d.
(24 h)
5 69(4 h)
82(20 min) 12 n. d.
(24 h)n. d.
(24 h)
6 93(10 h)
92(6 h) 13 n. d.
(24 h)n. d.
(24 h)
791
(5 h)
93 (1 h)
71 (20 min)
OHHO
OH
HO OH
OHHO
OHHO
OHHO
OH
O O
OH
O
OHO
OHO
OH
H2N OH
OH
NO2
OH
O2N
OH
OH
ROEt
O OO O
R+
phenol ethyl acetoacetate
[O=P(2-py)3Mo(CO)(NO)2](BF4)21 mol%
120 oC
32
Thermal HeatingThermal Heating
Convection transition
Liquid boiling temperature is always lower than surface temperature of container
33
Mechanism of Microwave Heating
Dipole RotationDipole Rotation
34
Ionic Ionic ConductionConduction
35
Interactive Characteristic between Interactive Characteristic between Materials and MicrowaveMaterials and Microwave
Conductor (Metal Material)
Reflective
Insulator (Telflon) Transparen
t
Dielectric Materials (Water)
Absorptive
36
Microwave Flash HeatingMicrowave Flash Heating
Microwave energy
Liquid raises temperature quickly
Digestion bottle
37
Preparation of Organomolybdenum CatalystPreparation of Organomolybdenum Catalyst
Microwave Flash Heating ConditionsMicrowave Flash Heating Conditions
NN
N
NN
N
Mo
OC
COOC
P
O
uw(300W/100%)/ 120 oC/ 5 min
dry CH3CN
MoCO
CO
CO
COOC
OCP
O
90 % yield
NN
N
Mo
OC
COOC
P
O
2 eq NOBF4
0oC / stir 1 hrN
NN
Mo
ON
NOOC
P
O2+
(BF4-)2
dry CH3NO2
75 % yield
38
Organomolybdenum Lewis Acid Catalyzed Organomolybdenum Lewis Acid Catalyzed Pechmann Condensation Pechmann Condensation
Organomolybdenum Lewis Acid Catalyzed Organomolybdenum Lewis Acid Catalyzed Pechmann Condensation Pechmann Condensation
Microwave Flash Heating ConditionsMicrowave Flash Heating Conditions
OHHO
OHO
OHHO
OHOHHO
OHHOOH
HO OH
OH
OH
NO2 OH
O2N
Phenol
Resorcinol 1,3,5-trihydroxybenzene
3-methoxyphenol
Orcinol2-methylresorcinol
2-nitrophenol 4-nitrophenol
1-naphthol
Pyrogallol
O O
OHO
OHO H2N OH
3,5-dimethoxyphenol 3-aminophenolsesamol
OH
OH
ROEt
O O O O
R+
phenol ethyl acetoacetate
[O=P(2-py)3Mo(CO)(NO)2](BF4)21 mol%
mw, 120 oCneat or 0.5 ml [bmim]PF6
39
OH
ROEt
O O O O
R+
phenol ethyl acetoacetate
[O=P(2-py)3Mo(CO)(NO)2](BF4)21 mol%
mw, 120 oCneat or 0.5 ml [bmim]PF6
Entry
Phenol
Yield (%)Entr
yPhenol
Yield (%)
neat[Bmim]PF
6neat
[Bmim]PF6
1 93(7 min)
86(7 min) 8
80(15 min)
46
(17 min)
2 92(5 min)
83(3 min) 9
86(10 min)
69
(10 min)
389
(3 min)91
(1 min) 1066
(17 min)17
(17 min)
4 86(6 min)
90(2 min) 11 n. d.
(17 min)n. d.
(17 min)
5 73(15 min)
84(3 min) 12 n. d.
(17 min)n. d.
(17 min)
6 93(17 min)
51(17 min) 13 n. d.
(17 min)n. d.
(17 min)
791
(15 min)
68
(17 min)
OHHO
OH
HO OH
OHHO
OHHO
OHHO
OH
O O
OH
O
OHO
OHO
OH
H2N OH
OH
NO2
OH
O2N
OH
40
Microwave Flash Heating and Microwave Flash Heating and Power Supply CurvePower Supply Curve
Microwave Flash Heating and Microwave Flash Heating and Power Supply CurvePower Supply Curve
OHO
OEt
O
R
Mo
Microwave Power Supply Curve
0
20
40
60
80
100
120
0 2 4 6 8 10 12 14 16 18
Time (min)
Po
we
r (%
)
IL IL + 3-OH-phenol + Et-acetateIL + phenol + Et-acetate 3-OH-phenol + Et-acetatephenol + Et-acetate
Microwave Flash Heating Curve
20
40
60
80
100
120
140
0 2 4 6 8 10 12 14 16 18Time (min)
Tem
p. (
deg
ree
cels
ius)
IL IL + 3-OH-phenol + Et-acetateIL + phenol + Et-acetate 3-OH-phenol + Et-acetate
phenol + Et-acetate
41
OH
ROEt
O O O O
R+
phenol ethyl acetoacetate
[O=P(2-py)3Mo(CO)(NO)2](BF4)21 mol%
120 oCneat or 0.5 ml [bmim]PF6
Entry PhenolThermal / Yield (%) MW / Yield (%)
neat [Bmim]PF6 neat [Bmim]PF6
1 98(1 h)
91 (1 h)
69 (20 min)
93(7 min)
86 (7 min)
94 (8 min)
2 80(25 min)
84(20 min)
92(5 min)
83(3 min)
375
(15 min)82
(10 min)89
(3 min)91
(1 min)
4 69(15 min)
84(15 min)
86(4 min)
90(2 min)
5 69(4 h)
82(20 min)
73(15 min)
84(3 min)
OHHO
OH
HO OH
OHHO
OHHO
OHHO
OH
42
OH
ROEt
O O O O
R+
phenol ethyl acetoacetate
[O=P(2-py)3Mo(CO)(NO)2](BF4)21 mol%
120 oCneat or 0.5 ml [bmim]PF6
Entry PhenolThermal / Yield (%) MW / Yield (%)
neat [Bmim]PF6 neat [Bmim]PF6
6 93(10 h)
92 (6 h)93
(17 min)51
(17 min)
791
(5 h)
93 (1 h)
71 (20 min)
91(15 min)
68
(17 min)
882
(10 h)
88
(5 h)
80(15 min)
46
(17 min)
984
(4 h)
92
(2 h)
86(10 min)
69
(10 min)
10 81(24 h)
88(10 h)
66(17 min)
17(17 min)
O O
OH
O
OHO
OHO
OH
H2N OH
43
Recyclability of Organomolybdenum Lewis AciRecyclability of Organomolybdenum Lewis Acid Catalystd Catalyst
Recyclability of Organomolybdenum Lewis AciRecyclability of Organomolybdenum Lewis Acid Catalystd Catalyst
CatalystSolution
Substrate Adduct
Added Extraction
Ionic Liquid[Bmim]PF6
CHCl3
44
Recyclability of Organomolybdenum LeRecyclability of Organomolybdenum Lewis Acid Catalyst in [bmim]PFwis Acid Catalyst in [bmim]PF66
Recyclability of Organomolybdenum LeRecyclability of Organomolybdenum Lewis Acid Catalyst in [bmim]PFwis Acid Catalyst in [bmim]PF66
OH
OEt
O OO O
+
[O=P(2-py)3Mo(CO)(NO)2](BF4)25 mol%
120 oC[bmim]PF6
OO
Catalyst 1 Recycling in [Bmim]PF6
0102030405060708090
100
0 1 2 3 4 5 6 7
number of experiment
an
aly
tic
yie
ld (
%)
45
Proposed MechanismProposed MechanismProposed MechanismProposed Mechanism
N NN
P
MoNOOC
O
NO
2+
( BF4- )2
- CON NN
P
MoNO
O
NO
2+
( BF4- )2
OEt
O
N NN
P
MoNO
O
NO
2+
( BF4- )2
OEt
O
nucliphilic attack
OEt
O
O
O
RHO
RHO
O
£_+
Mo
46
Proposed MechanismProposed MechanismProposed MechanismProposed Mechanism
O
O OO
HO
OEt
O
R-EtOH
MoMo
O
O OH
Mo
OO
OH
Mo
£_+O
OH
O
H
Mo
O
O
O
O O
H
H
MoMichaeladdition -H+
+H+
N NN
P
MoNO
O
NO
2+
( BF4- )2+
R R
RR R
R
47
Catalytic Reactivity of [A(2-py)3M(CO)(NO)2]2+ on Pechmann Condensation
Catalytic Reactivity of [A(2-py)3M(CO)(NO)2]2+ on Pechmann Condensation
CatalystsCatalystsYield (%)Yield (%)
A(2-py)A(2-py)33 MM
O=P(2-py)O=P(2-py)33 MoMo 9898
P(2-py)P(2-py)33 MoMo 8282
O=P(2-py)O=P(2-py)33 WW 7474
P(2-py)P(2-py)33 WW 7171
OH
OEt
O OO O
+
[A(2-py)3M(CO)(NO)2](BF4)21 mol%
120 oCneat, 1h
HO HOOH
OEt
O OO O
+
[A(2-py)3M(CO)(NO)2](BF4)21 mol%
120 oCneat, 1h
HO HO
48
Catalytic Reactivity of [A(2-py)3M(CO)(NO)2]2+ on Mukaiyama Aldol Reaction
Catalytic Reactivity of [A(2-py)3M(CO)(NO)2]2+ on Mukaiyama Aldol Reaction
CatalystsCatalystsYield (%)Yield (%)
A(2-py)A(2-py)33 MM
O=P(2-py)O=P(2-py)33 MoMo 9393
P(2-py)P(2-py)33 MoMo 8585
O=P(2-py)O=P(2-py)33 WW 5656
P(2-py)P(2-py)33 WW 4545
李婉甄碩士論文 ‘有機鉬金屬路易士酸在微波中對於 Mukaiyama Aldol 反應催化活性之探討’ 中正大學化學研究所 , 2005.
Cl3C
O
Si(CH3)3
DMF, 40oC, 5h
10 mol%Cl3C
OH[A(2-py)3M(CO)(NO)2](BF4)2
49
Catalytic Reactivity of [A(2-py)Catalytic Reactivity of [A(2-py)33M(CO)M(CO)(NO)(NO)22]]2+ 2+ on Diels Alder Reactionon Diels Alder Reaction
Catalytic Reactivity of [A(2-py)Catalytic Reactivity of [A(2-py)33M(CO)M(CO)(NO)(NO)22]]2+ 2+ on Diels Alder Reactionon Diels Alder Reaction
CatalystsCatalystsConcentration (M)Concentration (M)
/Time (min)/Time (min) Yield (%) (endo: exo)Yield (%) (endo: exo)A(2-py)A(2-py)33 MM
O=P(2-O=P(2-py)py)33
aa WW 0.67 / 450.67 / 45 97 (90:10)97 (90:10)
O=P(2-py)O=P(2-py)33bb MoMo 0.67 / 450.67 / 45 85 (90:10)85 (90:10)
P(2-py)P(2-py)33cc WW 0.022 / 300.022 / 30 87 (94:6)87 (94:6)
a: 陳宜宏碩士論文 “水溶性有機鎢金屬路易士酸在綠色溶劑及微波中對於 Diels-Alde 反應的影響”中正大學化學研究所 , 2003.
b: 李婉甄碩士論文 ‘有機鉬金屬路易士酸在微波中對於 Mukaiyama Aldol 反應催化活性之探討’ 中正大學化學研究所 , 2005.
c: 傅耀賢博士論文 “過渡金屬錯合物觸媒的合成、催化活性以及動力學研究 中正大學化學研究所 , 2001
bmimPF6
[A(2-py)3M(CO)(NO)2](BF4)23 mol%
O
O
50
ConclusionsConclusionsConclusionsConclusions
We have successfully demonstrated the catalytic activity of [O=P(2-py)3Mo(CO)(NO)2](BF4)2 for the synthesis of a variety of coumarins under solvent-free and ionic liquid system ([Bmim]PF6) conditions. This practical and simple method led to good yields of the coumarin derivatives under mild conditions and within short times.
The time economy, along with the conservation of the organomolybdenum Lewis acid catalyst activity and the high recovery of the Lewis acid catalyst, play for both low environmental impact and low cost. Other green advantages of the procedure are the low formation of wastes, easy purification; and principally, the replacement of corrosive and environmental unfriendly acids.
51
ConclusionsConclusionsConclusionsConclusions
The successful use of microwave irradiation in providing this rapid and direct route to coumarins in comparison to classical procedures contributes to confirming the participation of specific effects in some microwave-assisted organic synthesis.
Because the [O=P(2-py)3Mo(CO)(NO)2](BF4)2 catalyst is relatively high moisture – and oxygen – stability, we use neutral ionic liquids, [Bmim]PF6, for Pechmann condensation as a recyclable media, and still have good yield for several times.
52
OH
ROEt
O O O O
R+
phenol ethyl acetoacetate
[O=P(2-py)3Mo(CO)(NO)2](BF4)21 mol%
120 oCneat or 0.5 ml [bmim]PF6
Entry PhenolThermal / Yield (%) MW / Yield (%)
neat [Bmim]PF6 neat [Bmim]PF6
11 n. d.(24 h)
n. d.(24 h)
n. d. (17 min)
n. d. (17 min)
12 n. d.(24 h)
n. d.(24 h)
n. d. (17 min)
n. d. (17 min)
13 n. d.(24 h)
n. d.(24 h)
n. d. (17 min)
n. d. (17 min)
OH
NO2
OH
O2N
OH