Rahman Shah Zaib Saleem Michiggyan State …...Synthesis utilizing Povarov reaction= 6 (core...
Transcript of Rahman Shah Zaib Saleem Michiggyan State …...Synthesis utilizing Povarov reaction= 6 (core...
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Rahman Shah Zaib Saleem
Michigan State Universityg y
October 24, 2007
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Outline• INTRODUCTION• REACTION INSIGHT
Outline
• VARIANTS OF POVAROV REACTION• SINGLE ELECTRON MECHANISM• ASYMMETRIC CATALYSIS• CONCLUSIONS• CONCLUSIONS
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Outline• INTRODUCTION
– HISTORYPOTENTIAL APPLICATIONS
Outline
– POTENTIAL APPLICATIONS• REACTION INSIGHT• VARIANTS OF POVAROV REACTION• SINGLE ELECTRON MECHANISMSINGLE ELECTRON MECHANISM• ASYMMETRIC CATALYSIS• CONCLUSIONS
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Introduction: DiscoveryIntroduction: Discovery1962
Povarov and Mikhailov
Potential of generating 3 chiral centers in a single step
BF3.OEt2 pTsOH
R1=OR, SR
Considered as inverse electron demand aza-Diels Alder reactionConsidered as inverse electron demand aza-Diels Alder reaction
Reaction is also cited in the literature by the names:- Imino-Diels Alder reaction
A a Diels Alder reaction
Povarov, L. S. Russ. Chem. Rev. 1967, 36, 656-670.
- Aza-Diels Alder reaction
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Introduction: Reaction revisitedIntroduction: Reaction revisited
TFA
MeCN, r.t.
Grieco, P. A.; Bahsas, A. Tet. Lett. 1988, 29, 5855-5858.
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Introduction: Reaction revisitedIntroduction: Reaction revisited
NXTFA
MeCN, r.t.
X
Grieco, P. A.; Bahsas, A. Tet. Lett. 1988, 29, 5855-5858.
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Potential applications in total synthesisPotential applications in total synthesisHOOC Cl
N
OH NH OMe
VirantmycinMartinelline
O
NH
OHO
Helquinoline
y
NO
O
N
N
NO
HO O
ON
Isoschizogamine
CamptothecinDynemycin
Luotonin AMartinellic acidGalipinine
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Outline• INTRODUCTION• REACTION INSIGHT
Outline
– MECHANISM– CONTROL OF REGIOSELECTIVITY– STEREOCHEMICAL OUTCOME
• ACYCLIC DIENOPHILE– MONOSUBSTITUTED– DISUBSITUTED
• CYCLIC DIENOPHILE• VARIANTS OF POVAROV REACTION• SINGLE ELECTRON MECHANISM• ASYMMETRIC CATALYSIS• CONCLUSIONS
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Mechanism:Mechanism:
N
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Mechanism: Concerted or stepwiseMechanism: Concerted or stepwise
Catalyst
R1=R2R R
Products that can be formed
by concerted mechanism
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Mechanism: Concerted or stepwiseMechanism: Concerted or stepwise
Catalyst
R1=R2R R
Product that can NOT be formed
by concerted mechanismby concerted mechanism
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Mechanism: Concerted or stepwiseMechanism: Concerted or stepwise
BF3.OEt2PhMe, r.t.
E d
+
ExoEndo Exo
Alves, M. J.; Azoia, N. G.; Fortes, A. G. Tetrahedron. 2007, 63, 727-734.
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Mechanism: StepwiseMechanism: Stepwise
BF3.OEt2PhMe, r.t.
MeO MeO
NCO2Et
H
|+_BF3
N
CO2Et
H
Alves, M. J.; Azoia, N. G.; Fortes, A. G. Tetrahedron. 2007, 63, 727-734.
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ExplanationExplanationNH2 H
NN
TFA
HCHOTFA, MeCN
++
HN
NH
MeCN
NH2 HN
TFA, MeCN TFA, MeCN+
Mellor, J. M.; Merriman, G. D.; Riviere, P. Tet. Lett. 1991, 32, 7103-7106.
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ExplanationPhOH
Explanation
O NH2 O HNPh
O NH
TFA
MeCN+ ++
O O O
r.t. 1.5h 56% 39%
Reflux 1.5h 82% 17%
O NH2
TFA
O
MeCN+
Mellor, J. M.; Merriman, G. D. Tetrahedron. 1995, 51, 6115-6132.
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Control of regioselectivityControl of regioselectivity
BF3.OEt2+ +
4
r.t. 70 min
80%
2
Crousse, B.; Begue, J.; Bonnet-Delpon, D. J. Org. Chem. 2000, 65, 5009-5013.
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Rationale for control of regioselectivityRationale for control of regioselectivity
O
O
LA= Lewis Acid
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Stereochemical outcomeStereochemical outcome• Acyclic dienophiles
•Monosubsitituted•Monosubsitituted•Disubstituted
•Cyclic Dienophile
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Stereochemical outcome li di hilStereochemical outcome- acyclic dienophile
OMe
N CO Et
OMe
MeOBF3.OEt2PhMe, r.t.+ +
NH
CO2Et,45 min44% Cis Trans
Axial substituent
less favoredH H
Equitorial
NH
MeO
COOEtMeO
Alves, M. J.; Azoia, N. G.; Fortes, A. G. Tetrahedron. 2007, 63, 727-734.
substituent
more favoredCis Trans
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Example from literatureExample from literature
InCl3 (10 mol%)
MeCN, r.t.
Entry R1 R2 R3 Time(h) Yield(%)
1 H OMe H 2 901 H OMe H 2 90
2 H Me H 2 71
3 H Me Cl 2 76
4 OMe H Cl 3 704 OMe H Cl 3 70
5 H Me OMe 2 72
6 H OMe OMe 2 80
7 Me Me Cl 3 79
Sridharan, V. Perumal, P. T. Avendaño, C. J. Menéndez, C. Org. & Biomol Chem 2007, 5, 1351-1353.
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Example from literatureExample from literature
BF3.OEt2DCM, r.t.
Entry R1 R2 R3 Time(h) Yield(%) Cis:Trans1 H H H 2 98 98:2
Cis Trans
1 H H H 2 98 98:2
2 H H Me 2 96 96:4
3 H H OMe 2 90 96:4
4 OMe H OMe 3 94 98:24 OMe H OMe 3 94 98:2
5 H H Br 2 96 98:2
6 H H Cl 3 96 98:2
7 H H F 2 92 95:5
8 Me H H 3 89 90:10
Nikitina, E. V.; Kouznetsov, V. V.; Cruz, U. M.; Zubkov, F. I. Synthesis. 2007, 375-384.
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Stereochemical outcome A li Di hilStereochemical outcome- Acyclic Dienophile
BF3.OEt2PhMe, r.t.
R= Aromatic, -OMe, -OAc
RR
H
R
R= Aliphatic, bulky group (-OTBS)
Alves, M. J.; Azoia, N. G.; Fortes, A. G. Tetrahedron. 2007, 63, 727-734.
R
R
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Stereochemical outcome C li di hilStereochemical outcome- Cyclic dienophile
O NH
O
CO2Et
BF3.OEt2PhMe, r.t.
+ +
H
O
H
RR
H
Chelation fovored
Alves, M. J.; Azoia, N. G.; Fortes, A. G. Tetrahedron. 2007, 63, 727-734.
Sterically favored
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Example from literature
OR4
Example from literature
NH
O
PhR1
R2
R3R4
CAN(5 mol%)MeCN, r.t.
+ + +
Entry R1 R2 R3 R4 Time(h) Yield(%) Cis:Trans1 H H H H 2 83 57:43
Cis Trans
1 H H H H 2 83 57:43
2 H H Cl H 2 80 55:45
3 H H Br H 1.5 79 55:45
4 H H F H 4 70 55:45
5 H H Me H 4 70 60:40
6 H Me H Me 4 75 55:45
7 Me H Me H 6 85 55:45
Sridharan, V.; Avendaño, C. J.; Menéndez, C. Synlett. 2007, 1079-1082 .
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Outline• INTRODUCTION• REACTION INSIGHT
Outline
• VARIANTS OF POVAROV REACTION– ABC VS ABB TYPE REACTION
• SYNTHESIS OF MARTINELLINE– REVERSING THE REGIOSELECTIVITY
• SYNTHESIS OF LUOTONIN A– ALKYNYL DIENOPHILE
• SYNTHESIS OF CAMPTOTHECIN AND LUOTONIN A– DOUBLE POVAROV REACTION
• SYNTHESIS OF JULOLODINES• SINGLE ELECTRON MECHANISM• ASYMMETRIC CATALYSIS
CONCLUSIONS• CONCLUSIONS
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ABB t tiABB type reaction
OGdCl3
(20 mol%)MeCN, r.t.
+ +
NH
Ph
A
eC , t
88%B C
InCl3(10 mol%)H2O, r.t.
85%
+ +
85%
A B B
Li, C.; Zhang, J. H. J. Org. Chem. 2002, 67, 3969-3971.
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M h iMechanismIn+3 In+3
In+3
H2OOHO
N
In+3
OH
InCl3(10 mol%)H2O, r.t.+ +
A B B
Li, C.; Zhang, J. H. J. Org. Chem. 2002, 67, 3969-3971.
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E l f lit tExample from literature
InCl3(10 mol%)H2O, r.t.
Entry R Temp Time(h) Yield(%) Cis/Trans
Cis Trans
1 Me r.t. 4 84 81:19
2 OMe r.t. 4 81 87:13
3 F r.t. 10 81 86:14
4 NHPh t 10 65 86 144 NHPh r.t. 10 65 86:14
5 CN r.t. 24 46 69:31
Li, C.; Zhang, J. H. J. Org. Chem. 2002, 67, 3969-3971.
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E l f lit tExample from literatureCAN
(5 mol%)(5 mol%)MeCN, r.t.
Cis Trans
Entry R1 R2 R3 Time(min) Yield(%) Cis/Ttrans1 H H Et 60 75 89/11
2 H H nPr 60 73 91/92 H H Pr 60 73 91/9
3 H H nBu 60 76 91/9
4 OMe H Et 45 80 90/10
5 OMe H nPr 45 88 91/9
6 OMe H nBu 45 90 93/7
7 H Me Et 60 72 87/13
8 H OMe Et 120 75 85/15
Sridharan, V.; Avendaño, C. J.; Menéndez, C. Tetrahedron. 2007, 63, 673-681.
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Application in total synthesisApplication in total synthesis
•Martinelline & Martinellic acid
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Martinelline & Martinellic acidMartinelline & Martinellic acid• Source: Roots of Martinella iquitosensis (lowland Amazon rainforest plant) • Isolated by: Merck group1
Synthesis utilizing Povarov reaction= 6 (core synthesis= 4, total synthesis=2)
y g p• Biological evaluation: First non-peptide bradykinin receptor inhibitor2
Martinelline
M t i lli id
1Witherup, K. M.; Ransom, R. W.; Graham, A. C.; Varga, S. L.; J. Am. Chem. Soc. 1995, 117, 6682–6685.2Xia, C. F.; Heng, L.; Ma, D.; Tet. Lett. 2002, 43, 9405-9409.
Matrinellic acid
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Martinelline & Martinellic acidMartinelline & Martinellic acid
Approaches other than Povarov reaction to build the key intermediate:
Ma, D. Xia, C. Jiang, J. Zhang, J. Org. Lett. 2001, 3, 2189-2191.
Ma, D. Xia, C. Jiang, J. Zhang, J. Tang, W. J. Org. Chem. 2003, 68, 442-451.
19 steps
18 stepsSnider, B. B. Ahn, Y. O’Hare, S. M. Org. Lett. 2001, 3, 4217-4220.
p9 steps
Approaches using Povarov reaction to build intermediate
Powell, D. A. Batey, R. A. Org. Lett. 2002, 4, 2913-2916.
13 steps2 steps
Xia, C. F. Heng, L. Ma, D. Tet. Lett. 2002, 43, 9405-9409.
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Martinelline & Martinellic acid
Cb
Martinelline & Martinellic acid
CO2Me
NCbz
2NH
MeO2CN
Cbz
N
MeO2CN
Cbz
NHCbzNHCbz
MeCN, r.t.48 h
NH2HN
H
Cat. Pd(OH)2, H2r.t. 5 h
Dy(OTf)3 92% 85 : 15CSA 74% 11 : 89
89%
Powell, D. A.; Batey, R. A. Org. Lett. 2002, 4, 2913-2916.
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Outline• INTRODUCTION• REACTION INSIGHT
Outline
• VARIANTS OF POVAROV REACTION– ABC VS ABB TYPE REACTION
• SYNTHESIS OF MARTINELLINE– REVERSING THE REGIOSELECTIVITY
• SYNTHESIS OF LUOTONIN A– ALKYNYL DIENOPHILE
• SYNTHESIS OF CAMPTOTHECIN AND LUOTONIN A– DOUBLE POVAROV REACTION
• SYNTHESIS OF JULOLODINES• SINGLE ELECTRON MECHANISM• ASYMMETRIC CATALYSIS
CONCLUSIONS• CONCLUSIONS
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2 3 Disubsitution2,3-Disubsitution
BF3.OEt2r.t.
OO
O
NH
CF3
OBF3.OEt2
r.t.
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2 3 Disubsitution2,3-Disubsitution
R
NH
R'
RS S
NH
R'
RSc(OTf)3
MeCN, r.t.NiCl2/NaBH4
THF
’
1
Entry R’ R Time(h) Yield(%) 1(Trans/Cis)1 p-(C6H4)CO2Me Ph 3 81 23/1
2 Ph Bn 1 ¼ 82 28/1
3 iBu Bn 1 66 1/13 iBu Bn 1 66 1/1
4 iBu Ph 1 64 2/1
Cheng, D.; Zhou, J.; Saiah, E.; Beaton, G. Org. Lett. 2002, 4, 4411-4414.
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Application in total synthesisApplication in total synthesis
Another example of 2,3-Disubstitution
•Luotonin A
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Luotonin ALuotonin A
• Source: Peganum nigellastrum (Chinese medicinal plant )1• Source: Peganum nigellastrum (Chinese medicinal plant )• Isolated by: Hano and co-workers2
• Biological evaluation: Cytotoxic antitumor alkaloid
Synthesis Publications using Povarov reaction: 2
1 Osborne, D.; Stevenson, P. J. Tet. Lett. 2002, 43, 5469-5470. 2Twin, H.; Batey, R. A. Org. Lett. 2004, 6, 4913-4916.
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Luotonin ALuotonin A4 step total synthesis
i) Y(OTf)3 (3 mol%) AnilineMeCN, r.t. 12 h 97%
ii) HCl, MeCN, reflux, 1 h 78%
NaOEtEtOH78oC99%99%
Microwave, 7 min 85%
Osborne, D.; Stevenson, P. J. Tet. Lett. 2002, 43, 5469-5470.
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Outline• INTRODUCTION• REACTION INSIGHT
Outline
• VARIANTS OF POVAROV REACTION– ABC VS ABB TYPE REACTION
• SYNTHESIS OF MARTINELLINE– REVERSING THE REGIOSELECTIVITY
• SYNTHESIS OF LUOTONIN A– ALKYNYL DIENOPHILE
• SYNTHESIS OF CAMPTOTHECIN AND LUOTONIN A– DOUBLE POVAROV REACTION
• SYNTHESIS OF JULOLODINES• SINGLE ELECTRON MECHANISM• ASYMMETRIC CATALYSIS
CONCLUSIONS• CONCLUSIONS
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Alk l di hil
R1
COOEtS
S
Alkynyl dienophile
N R2
R1CF3SO3HDCM, r.t.
5min
Entry R1 R2 Yield(%)1 Me 4-NO2-C6H4 59
2 Me 4-MeO-C6H4 72
3 Me 4-F-C6H4 63
4 Me 4-Cl-C6H4 68
5 H 4-MeO-C6H4 71
6 H 4-F-C6H4 63
7 Cl 3,4-CH2O2-C6H3 59
8 Cl 4-NO2-C6H4 57
Wang, S.; Zhao, Y. L.; Zhang, W.; Liu, Q. J. Org. Chem. 2007, 72, 4985-4988
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Application in total synthesisApplication in total synthesis
•Camptothecin•Luotonin A
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CamptothecinCamptothecin• Source: Camptotheca acuminata• Isolated by: Wall and co-workers• Biological evaluation: Potent antitumour alkaloid
Wall, M. E.; Wani, M. C.; Cook, C. E.; Palmer, K. H., Sim, G. A. J. Am. Chem. Soc. 1966, 88, 3888-3890.
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CamptothecinCamptothecin
Dy(OTf)3 (10 mol%)
MeCN, 16 h, 50oC
71%
NN
O
Precursor used in the formal synthesis of camptothecin
NH CN
Twin, H.; Batey, R. A. Org. Lett. 2004, 6, 4913-4916.
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Luotonin ALuotonin A6 step total synthesisp y
Twin, H.; Batey, R. A. Org. Lett. 2004, 6, 4913-4916.
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Luotonin ALuotonin A6 step total synthesisp y
NH2
+ Dy(OTf)3 (10 mol%)
MeCN, 24 h, r.t.
51%
Twin, H.; Batey, R. A. Org. Lett. 2004, 6, 4913-4916.
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Outline• INTRODUCTION• REACTION INSIGHT
Outline
• VARIANTS OF POVAROV REACTION– ABC VS ABB TYPE REACTION
• SYNTHESIS OF MARTINELLINE– REVERSING THE REGIOSELECTIVITY
• SYNTHESIS OF LUOTONIN A– ALKYNYL DIENOPHILE
• SYNTHESIS OF CAMPTOTHECIN AND LUOTONIN A– DOUBLE POVAROV REACTION
• SYNTHESIS OF JULOLODINES• SINGLE ELECTRON MECHANISM• ASYMMETRIC CATALYSIS
CONCLUSIONS• CONCLUSIONS
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JulolodinesJulolodinesFluorescent probes, photoconductive materials, potential antidepressants and tranquilizers.
HN
R1
R2
N
R1
R2R3
TFE, r.t. 35% CH2O,
TFE, 1 h
i-Prn-C5H11i-Pr
N
OEtEtO
72%
N
OEtEtO
N
OEtO
35%
Legros, J.; Croousse, B.; Ourevitch, M.; Bonnet-Delpon, D. Synlett. 2006, 1899-1902.
72%80%35%
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Outline• INTRODUCTION• REACTION INSIGHT
Outline
• VARIANTS OF POVAROV REACTION• SINGLE ELECTRON MECHANISM• ASYMMETRIC CATALYSIS• CONCLUSIONS• CONCLUSIONS
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Single electron mechanismSingle electron mechanism
NH
NR1
ONO+BF4
-
DCM, r.t.H
R2
Wu, L.; Zhou, Y. L.; Jia, X.; Li, R.; Liu, Z.Tet. Lett. 2005, 46, 8937-8939.
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Single electron mechanismSingle electron mechanism
O
N
NR1
2
O
N
O
R2
N O
N
NR1
R2
OH
R2
Wu, L.; Zhou, Y. L.; Jia, X.; Li, R.; Liu, Z.Tet. Lett. 2005, 46, 8937-8939.
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Single electron mechanismSingle electron mechanismN
1
O
NH
R1
R2
NO+BF4-
DCM, r.t.
Entry R1 R2 Time(h) Yield(%)1 OMe H 3 72
2 Me NO2 1.5 91
3 H OMe 2 89
4 H H 1 94
5 H NO 1 645 H NO2 1 64
6 Br H 1 95
7 Cl H 1 96
Wu, L.; Zhou, Y. L.; Jia, X.; Li, R.; Liu, Z.Tet. Lett. 2005, 46, 8937-8939.
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Outline• INTRODUCTION• REACTION INSIGHT
Outline
• VARIANTS OF POVAROV REACTION• SINGLE ELECTRON MECHANISM• ASYMMETRIC CATALYSIS
– ASYMMETRIC METAL CATALYSIS– ASYMMETRIC METAL CATALYSIS– ASYMMETRIC BRONSTED ACID CATALYSIS
• CONCLUSIONS
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Asymmetric metal catalysisAsymmetric metal catalysis
Catalyst
OH
NH
Ph NH
Ph
OH
OH53% Yield, no chiral induction
N
Yb(OTf)3 Catalyst =
Ishitani, H.; Kobayashi, S. Tet. Lett. 1996, 37, 7357-7360.
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Screening of additiveScreening of additive
Catalyst
OH
NH
Ph NH
PhOH OH
E t Additi ( l%) T (oC) Yi ld(%) Ci /T % (Ci )
OH
OHCatalyst = , DBUYb(OTf)3 Additive =
Entry Additive (mol%) Temp.(oC) Yield(%) Cis/Trans ee% (Cis)
1 DTBP (100) 0 67 99/1 61
2 DTBMP(100) -15 82 >99/1 70
3 DTBP(100) 15 92 >99/1 71
Ishitani, H.; Kobayashi, S. Tet. Lett. 1996, 37, 7357-7360.
3 DTBP(100) -15 92 >99/1 71
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Substrate scopeSubstrate scope
Yb Complex(10-20 mol%)
Additive (100 mol%)DCM, -15oC, MS4Ǻ
Entry R’ R Additive Catalyst Yield(%) Cis/Trans ee% mol% (Cis)
1 Ph Et DTBP 20 58 94/6 61
2 Ph Et DTBP 10 52 94/6 77
3 α Naphthyl Et DTBP 20 69 >99/1 863 α-Naphthyl Et DTBP 20 69 >99/1 86
4 α-Naphthyl Et DTBMP 20 74 >99/1 91
5 α-Naphthyl Bu DTBMP 20 80 66/34 70
Ishitani, H.; Kobayashi, S. Tet. Lett. 1996, 37, 7357-7360.
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Substrate scopeSubstrate scope
NH
R'
Yb Complex(10-20 mol%)
Additive (100 mol%)DCM, MS4Ǻ HOH
Entry R’ R Additive Catalyst mol%
Temp. (oC)
Yield (%)
Cis/ Trans
ee% (Cis)
DCM, MS4Ǻ
mol% ( C) (%) Trans ( )
1 α-Naphthyl Dihydrofuran DTBMP 20 -15 90 91/9 78
2 α-Naphthyl Dihydrofuran DPP 20 -15 67 93/7 86
3 α-Naphthyl Cyclopentadiene DTBMP 20 -15 69 >99/1 68
4 Cyclohexyl Cyclopentadiene DTBMP 20* -15 58 >99/1 73
*Sc(OTf)3 used
Ishitani, H.; Kobayashi, S. Tet. Lett. 1996, 37, 7357-7360.
( )3
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Explanation of enantioselectivityExplanation of enantioselectivityYb Complex(10-20 mol%)
Additive (100 mol%)Additive (100 mol%)DCM, MS4Ǻ
Ishitani, H.; Kobayashi, S. Tet. Lett. 1996, 37, 7357-7360.
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Asymmetric Bronsted acid catalysisAsymmetric Bronsted acid catalysis
ORCatalyst(10 mol%)
NH
R'OH
Toluene
Akiyama, T.; Morita, H.; Fuchibe, K. J. Am. Chem. Soc. 2006, 128, 13070-13071.
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Substrate scopeSubstrate scopeORCatalyst
(10 mol%)
T l NH
R'OH
Entry R’ R Temp. Yield(%) Cis/Trans ee(%) for Cis
Toluene
1 Ph Et -10oC 89 99/1 94
2 Ph nBu -10oC 82 99/1 96
3 Ph Bn 0oC 76 99/1 91
4 2-BrC6H4 Et -10oC 77 99/1 90
5 2-BrC6H4nBu -10oC 86 99/1 89
6 2-ClC6H4 Et -10oC 79 99/1 88
7 2-MeC6H4 Et 0oC 59 99/1 91
8 2-ClC6H4 Et 0oC 72 96/4 87
9 2-naphthyl Et 0oC 74 99/1 95
10 2 naphthyl nBu 0oC 80 99/1 8810 2-naphthyl nBu 0oC 80 99/1 88
Akiyama, T.; Morita, H.; Fuchibe, K. J. Am. Chem. Soc. 2006, 128, 13070-13071.
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Explanation of enantioselectivityExplanation of enantioselectivityORCatalyst
(10 mol%)
T l NH
R'OH
Toluene
Akiyama, T.; Morita, H.; Fuchibe, K. J. Am. Chem. Soc. 2006, 128, 13070-13071.
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Recent developmentsRecent developments
O NH
O
Catalyst
H
Woll, M. G.; Jacobsen, E. N. Manuscript in preparation
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Recent developmentsRecent developments
ON
R' OCatalyst
ON
R NH
Catalyst=y
Entry R’ R Yield(%) Trans/Cis ee(%) for Trans1 H H 86 4:1 942 H OMe 90 3:1 883 H NO2 82 3:1 934 H Br 94 4:1 945 OMe H 92 3:1 93
Woll, M. G.; Jacobsen, E. N. Manuscript in preparation
6 Br H 85 5:1 91
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Outline• INTRODUCTION• REACTION INSIGHT
Outline
• VARIANTS OF POVAROV REACTION• SINGLE ELECTRON MECHANISM• ASYMMETRIC CATALYSIS• CONCLUSIONS• CONCLUSIONS
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ConclusionConclusion
•Highly regioselective reaction with good diastereoselectivity•Highly regioselective reaction with good diastereoselectivity.•Mild reaction conditions (mostly room temperature).•Potential to ability to generate 3 stereocenters at a time.•Good tool for building library of compounds.
•Future prospects•Work to be done in the asymmetric Povarov reaction.•Synthesis of natural products using asymmetric form of the reaction.
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