Transcript Homogeneous Gold Catalysis – A Reactivity Perspective

Homogeneous Gold Catalysis – A
Reactivity Perspective
Dongxu Shu
Tang Research Group
12, 10, 2009
1
Contents
 Relativistic effect and reactivity
 π-acidity reactivity
 Gold catalyzed coupling reaction
 Summary
2
Features of Gold Catalysis
 π-acidity: soft Lewis acid, preferentially activate π-systems
 AuI and AuIII
 AuI: d10, linear bicoordinate geometry, difficult in asymmetric
catalysis
 Noβ-H elimination
 Reluctant to undergo oxidative addition and reductive elimination
3
Relativistic Effect
Lower 6s and 6p, higher 5d
Pyykko, P. et al. Acc. Chem. Res. 1979, 12, 276.
4
Origin of π–acidity and Alkynophilicity
•
π-acidity of R3PAu+
1)
2)
lower LUMO
poor back donation
•
1)
2)
Alkynophilicity
kinetic in origin
LUMO of alkyne is lower
R3P Au
Au
Nu
Au
Au
faster than Nu
Hertwig, R. H. et al. J. Phys. Chem. 1996, 100, 12253.
Toste, F. D. et al. Nature. 2007, 446, 395.
ΔG ≈ -10 kcal/mol
Au
5
Contents
 Relativistic effect and reactivity
 π-acidity reactivity
1. Alkyne
2. Enyne
3. Propargylic ester
4. Allene
 Gold catalyzed coupling reaction
 Summary
6
π-Acidity Reactivity
Nu
Nu
Nu
Au
E
Au
E
Nu
E
Au
L Au
R
L Au
R
Nu
E
Au
Rearrangement
Elimination
Nu attack
Cyclopropanation
C-H insertion
7
Carbene or Carbocation
Au
[(R3P)Au] [NTf2]
O
Au
O
O
O
NTf2
-78oC
Ph3PAu
1
2
3
O
O
AuPPh3
Ph3PAu
O
1
2
3
O
NTf2
Ph3PAu
O
1
2
3
O
<7.2 kcal/mol
Fürstner, A. et al. Angew. Chem. Int. Ed. 2009, 48, 2510.
8
Carbene or Carbocation
Ph3PAu
O
1
2
3
PMe3
Au
PMe3
Au
O
<7.2 kcal/mol
Calculated: 22.5 kcal/mol
Ph
O
Ph
LAuCl, AgSbF6
O
O
Ph
CD2Cl2
O
Ph
Ligand
Yield
P(OMe)3
P(OPh)3
PPh3
PMe3
NHC
0%
11%
52%
56%
80%
Ph
O
Ph
LAuCl, AgSbF6
O
Ph
CD2Cl2
O
Ph
O
Goddard, W. A. Toste, F. D. et al. Nature Chem. 2009, 1, 482.
9
Early Research
O
7 mol% H[AuCl4]
R1
R2
R1
R2
R1
R2 +
O
MeOH/H2O, 650C
Cl
OMe
+
+ R1
R1
R2
R2
Thomas, C. B. et al. J. Chem. Soc. Perkin Trans. II 1976, 1983.
Ph
Ph3PAuMe
MeSO3H
Ph + MeOH
solvent-free
20-50 0C
Ph3P Au
MeSO3
OMe
Ph
Ph
TOF: Ph3P (610 h-1) < (MeO)3P (1200 h-1) < (PhO)3P (1500 h-1)
TON: Ph3P (5000) > (PhO)3P (2500)
L Au
X
Teles, J. H. et al. Angew. Chem. Int. Ed. 1998, 37, 1415.
10
Stereoselectivity and Regioselectivity
Stereoselectivity
Au
anti
Au
Nu
Regioselectivity
Nu
R
R
R
Au
Au
Au
Au
Au
•
Au
R=H
5-exo-dig
O
Ph
N
R
O
Ph
Au
HN
R
R
R=H
6-endo-dig
O
Ph
O
H
Au(IPr)
H
N
N
Can be isolated
Ph
C Hg
Hashmi, A. S. K. et al. Angew. Chem. Int. Ed. 2009, 48, 8247.
11
Contents
 Relativistic effect and reactivity
 π-acidity reactivity
1. Alkyne
2. Enyne
3. Propargylic ester
4. Allene
 Gold catalyzed coupling reaction
 Summary
12
Reactivity Pattern of Enyne
Au
Au
Further transformation
Au
Au
Au
Furstner, A. et al. Angew. Chem. Int. Ed. 2008, 47, 5030.
13
Cycloisomerization of 1,6-Enyne With
Skeletal Rearrangement
1
Single Cleavage
2
MeOOC
3
MeOOC
[AuCl(PPh3)]/
AgSbF6 (2 mol%)
CH2Cl2, r.t., 25min
91%
4
2
MeOOC
MeOOC
1
4
t-Bu
t-Bu P Au NCMe
3
A
Echavarren, A.M. et al. Angew. Chem. Int. Ed. 2004, 14, 2402.
Double Cleavage
1
2
Me
MeOOC
MeOOC
3
4
[AuCl(PPh3)]/
AgSbF6 (2 mol%)
CH2Cl2, r.t., 5min
95%
4
MeOOC
MeOOC
1
2 Me
3
Echavarren, A.M. et al. Angew. Chem. Int. Ed. 2005, 44, 6146.
14
SbF6
Mechanism – From Cyclobutene?
A (2 mol%)
MeOOC
MeOOC
H
MeOOC
MeOOC
CH2Cl2, r.t.
(80%)
H
t-Bu
t-Bu P Au NCMe
SbF6
H
A
H
Au
Au
Conrotatory opening
Z
Z
H
H
25.7
MeOOC
MeOOC
Pd catalyst,
MeOOC
60 oC
MeOOC
COOMe
COOMe
21.6
Echavarren, A.M. et al. Chem. Eur. J. 2006, 12, 5916.
15
Mechanism of Skeletal Rearrangement
Au
R1
R1
R1
Au
R2
R2
R1
H
H
Au
R1
R1
R2
R1
R2
Single Cleavage
R2
Au
H
R1
R2
R2
H
R2
Double Cleavage
Echavarren, A.M. et al. Chem. Eur. J. 2006, 12, 5916.
16
Mechanism of Skeletal Rearrangement
Au
Au
MeOOC
H
MeOOC
O=SR2
Ph
MeOOC
Ph
MeOOC
H
MeOOC
H
MeOOC
Ph
MeOOC
H
H
H
O
SR2
Ph
MeOOC
MeOOC
MeOOC
MeOOC
O
Au
MeOOC
O=SR2
MeOOC
MeOOC
H
H
O
H
H
H
L= R N
N R
H
Toste, F. D. et al. J. Am. Chem. Soc. 2007, 129, 5838.
17
Contents
 Relativistic effect and reactivity
 π-acidity reactivity
1. Alkyne
2. Enyne
3. Propargylic ester
4. Allene
 Gold catalyzed coupling reaction
 Summary
18
Propargylic Ester Reactivity Pattern
R1
5-exo-dig
O
Au
R3
R3
O
R1
Carbene-type
reactivity
O
R2
R2
R1
O
O
O
Au
R2
R1
R3
Au
O
6-endo-dig
Au
O
R2
R2
R3
Au
•
O
R1
O
allene
activation
R3
overall [3,3] rearrangement
Nolan, S. P. et al. Angew. Chem. Int. Ed. 2007, 46, 2750.
19
5-exo-dig VS 6-endo-dig
OAc
OAc C-H insertion
5-exo-dig
R
Au
OAc
R=H
Au
R
1 R
1,2-shift
[3,3]
R = alkyl
Au
•
OAc
Nolan, S. P. et al. Angew. Chem. Int. Ed. 2006, 45, 3647.
O
18
O
6-endo-dig
•
Ph
Ph
2
18 O
t-Bu
18
Oac
R
R
Ph
t-Bu
O
O
Ph
O
Ph
Toste, F. D. et al. J. Am. Chem. Soc. 2009, 131, 4513.
t-Bu
Ph
20
Carbene Reactivity through 5-exo-dig
OAc
[RuCl2(CO)3]2
OAc
Ph
Ph
AuCl3 also work
Uemura, S. et al. Tetrahedron Lett. 2003, 44, 2019.
OAc
OAc
2.5% [Au], 5% AgSbF6
Ar
Ar
o
MeNO2, 25 C, 20min
76-94% e.e.
O
[Au] =
O
O
t-Bu
PAr2AuCl
PAr2AuCl
OMe
Ar =
t-Bu
O
Toste, F. D. et al. J. Am. Chem. Soc. 2005, 127, 18002.
21
Allene Activation through 6-endo-dig
Bu
N
O
[3, 3]
O
O
N
O
O
Bu
N
• [M]
Me
O
Bu
M
O
M=Au
O
Bu
O
Pt
N
O
>
Au
Bu
N
O
[M]
O
O
O
Bu
Pt
M=Pt
N
Bu
N
Zhang, L. et al. J. Am. Chem. Soc. 2005, 127, 16804.
Zhang, L. et al. J. Am. Chem. Soc. 2007, 129, 11358.
22
Contents
 Relativistic effect and reactivity
 π-acidity reactivity
1. Alkyne
2. Enyne
3. Propargylic ester
4. Allene
 Gold catalyzed coupling reaction
 Summary
23
Vinyl Allene as Substrate
Au
n-C5H11
n-C5H11
Au
n-C5H11
Au
n-C5H11
•
Au
n-C5H11
•
m-CPBA
n-C5H11
O
n-C4H9
CH2Cl2
65%
AuCl(PPh3) / AgSbF6 (2 mol%)
•
n-C4H9
CH2Cl2, r.t., 10min
80%
[O]
n-C5H11
O
O
n-C5H11
R1
R2
Malacria, M. et al. J. Am. Chem. Soc. 2009, 131, 2993.
R1
R2
24
Vinyl Allene as Substrate
AcO
AcO
OAc
AcO
Au
H
H
( )n
( )n
n = 1, 83%
n = 2, 97%
Au
( )n
( )n
n = 4, 100%
n = 5, 99%
n = 3, 86%
AcO Au
AcO
AcO
OAc
OAc
[3,3]
( )n
Au
•
Au
AcO
H
AcO
AcO
( )n
H
Au
AcO
H
H
H
AcO
Malacria, M. et al. J. Am. Chem. Soc. 2009, 131, 2993.
25
Allene for Cycloaddition
•
MeOOC
H
D
MeOOC
5%, LAuCl
5%, AgSbF6
MeOOC
CH2Cl2, r.t.
MeOOC
H
D
H
MeOOC
D
MeOOC
H
H
H
2
1
L
3
2:3
P(OPh)3
100:0
PPh3
67:33
P(t-Bu)2(o-biPh) 4:96
Toste, F. D. et al. J. Am. Chem. Soc. 2009, 131, 6348.
•
TsN
CH2Cl2, -15 oC
1
H
L*-AuCl, AgSbF6
TsN
L=
H
yield: 92%
ee: 92%
Mascarenas, J. L. et al. J. Am. Chem. Soc. 2009, 131, 13020.
O
O
Ph
P
N
Ph
26
Contents
 Relativistic effect and reactivity
 π-acidity reactivity
1. Alkyne
2. Enyne
3. Propargylic ester
4. Allene
 Gold catalyzed coupling reaction
 Summary
27
Early Investigation
I Me
Me Au PPh3
Ph3P Au Me
Me Me
PPh3
Me Au Me
Me
I
Me Me
Au PPh3
I Au PPh3
I Me
PPh3
Me Au I
Me
Me Au PPh3
Kochi, J. K. et al. J. Organomet. Chem. 1974, 64, 411.
Kochi, J. K. et al. J. Am. Chem. Soc. 1976, 98, 7599.
28
Gold Catalyzed Coupling Reaction
AuCl(PPh3)
I
K3PO4
Corma, A. et al. Angew. Chem. Int. Ed. 2007, 46, 1536.
nano Au (0.05 mol%)
Cl
(HO)2B
NaOH, H2O
Guo, R. et al. J. Am. Chem. Soc. 2009, 131, 386.
29
Combine the π-acidity and Coupling
Reactivity
H
Nu
H
R-M (B)
Nu
Nu
Nu
Nu
Au
Au
Au
R
M (Pd) Nu
M
R
Combine the π-acidity and Coupling
Reactivity
O
•
5mol%
AuCl3
OH
O
O
10%
47%
AuIII
R
R
R OH
•
O R
R O
AuIII
R
III
Au
AuIII
R
R O
R
O R
R
R
R
O
AuIII
Hashmi. A. S. K. et al. Eur. J. Org. Chem. 2006, 1387.
R
O
Combine the π-acidity and Coupling
Reactivity
O
O
O
O
HAuCl4 (5 mol%)
tBuOOH
O
O
yield: 13% - 67%
Wegner. H. A. et al. Chem. Eur. J. 2008, 14, 11310.
Oxidative Coupling
Me
O
OAc
O
[Ph3PAu]NTf2 (5 mol%)
Me
Bu
Bu
Bu
Selectfluor
O
Me
Me
19%
O
Bu
H
Bu
11%
O
Au
Bu
Me
F
Selectfluor
Me
F N
N
Cl
2 BF4
Zhang. L. et al. Angew. Chem. Int. Chem. 2009, 48, 3112.
Oxidative Coupling
Me
O
OAc
Bu
Bu
O
Me
O
L
F
Bu
[LAuI]
[LAuI]F
[3,3]
L= Ph3P
O
AuIII
Bu
Me
F
OAc
I
Bu
Au
Bu
Me
Me
O
Bu
L
AuIII
F
Me
L
H+, HOAc
O
III L
Au
Bu
AuI
Bu
F
Me
L
Me
R-M
N
F N
N
Cl
2 BF4
O
Bu
R
L
AuIII
F
Me
N
Cl
2 BF4
O
Reductive Elimination
Bu
OAc
• Au
Me
H2O
O
Bu
R
Me
Zhang. L. et al. Angew. Chem. Int. Chem. 2009, 48, 3112.
Me
OAc
Ph BXn
Me
Selectfluor (2 equiv)
Me
O
O
CH3CN, 80 oC
Bu
1
Solvent
1
Me
3
2
3
[Ph3PAu]NTf2
PhBF3K
MeCN
[Ph3PAu]NTf2
PhB(OCH3)2
MeCN
30%
60%
0%
[Ph3PAu]NTf2
PhB(OH)2
MeCN/H2O 20:1
50%
17%
9%
Ph3PAuCl
PhB(OH)2
MeCN/H2O 20:1
72%
9%
6%
PPh3 Au
only
Ph Ph
PhBF3K
PPh3 Au Ph
transmetallation
F-
PhB(OH)3
PPh3 Au F
PPh3
H
Bu
O
Me
2
Me
PhBXn
Bu
Bu
Bu
Catalyst
O
Ph
F
Au Ph
Ph
Ph Ph
Zhang. L. et al. Angew. Chem. Int. Chem. 2009, 48, 3112.
Gold and Palladium Combined for
Cross-Coupling
Me
Au(PPh3)Cl (1.0 eq.)
•
i-Pr
OEt
Ph3P
Au
Me
O
AgOTf (1.0 eq.)
O
O
i-Pr
Ph
PdIIL2
I
Ph
Ph
PdCl2(dppf)] (1 mol%)
I
Ph
O
I MeCN
Ph3P
Au
Me
i-Pr
O
Me
O
Me
i-Pr
[L2Pd0]
[L2PdCl2]
O
Ph
[Ph3PAuI]
O
i-Pr
Me
O
Ph
PdIIL2
i-Pr
Hashmi, A. S. K. et al. Angew. Chem. Int. Ed. 2009, 48, 8283.
Blum, S. D. et al. Organometallics. 2009, 28, 1275.
36
Summary

π-acidity reactivity
Complexity
1. substrate design
2. coupled with known reactivity (Nazarov, cycloaddition, carbocation)
3. tandem

Gold catalyzed coupling reaction

Combine π-acidity reactivity and coupling reaction
1. Generate more complexity
2. from stoichiometric to catalytic
37
Acknowledgement
 Professor Weiping Tang
 Tang Group
 Practice talk attendees
Jenny Werness
Wei Zhang
Renhe Liu
Dr. Suqing Zheng
Xiaoxun Li
Dr. Min Zhang
Patrick Robichaux Na Liu
 Katherine Myhre
Kyle Dekorver
Tianning Diao
38
R3P
Au
R3P Au
MeOOC
MeOOC
MeOOC
R3P
Au
MeOOC
MeOOC
•
MeOOC
R3P
Au
H
R3P
Au
MeOOC
MeOOC
MeOOC
MeOOC
MeOOC
MeOOC
Goddard, W. A.; Toste, F. D. et al. Org. Lett. 2009, 11, 4798.
Mascarenas, J. L. et al. J. Am. Chem. Soc. 2009, 131, 13020.
39
Relativistic Effect
• m=m0/[1-(v/c)2]1/2
• r decrease as m increase
• v increase, m increase, radius
decrease, s and p orbital lower, d
higher
• Unusual higher electronegativity, ionization energy,
lower 6s and 6p (LUMO), higher 5d, strong Au-L bond
Pyykko, P. et al. Acc. Chem. Res. 1979, 12, 276.
General Reactivities of Gold Catalysis
 π-Acidity:
Nu
[Au]
 Traditional organometallic reactivity:
Oxidative addition and reductive elimination
Transmetallation
 C-H activation:
H
H
 Hydrogenation and Oxidation
Au III
Au
Au
E
E
E