IT TAKES TWO TO TANGO:
RECENT ADVANCES IN
HOMOGENEOUS COOPERATIVE
DUAL CATALYSIS BY
TRANSITION METALS
JANELLE STEVES
UNIVERSITY OF WISCONSIN-MADISON
LITERATURE SEMINAR
FEBRUARY 23 RD , 2012
1
WHAT IS COOPERATIVE DUAL CATALYSIS?
two catalysts present at the onset of a reaction simultaneously and
selectively activate and couple two substrates
Traditional single-catalyst catalysis
Allen, A. E.; MacMillan, D. W. C. Chem. Sci. 2012, 3, 633-658
Shinde, V. S.; Gajula, B.; Patil, N. T. Org. Biomol. Chem. 2012, 10, 211-224
Cooperative dual catalysis
2
COOPERATIVE DUAL CATALYSIS
COMPARISON TO OTHER DUAL CATALYTIC PROCESSES
Lee, J. M.; Na, Y.; Han, H.; Chang, S. Chem. Soc. Rev. 2004, 33, 302-312
Allen, A. E.; MacMillan, D. W. C. Chem. Sci. 2012, 3, 633-658
Shinde, V. S.; Gajula, B.; Patil, N. T. Org. Biomol. Chem. 2012, 10, 211-224
3
COOPERATIVE CATALYSIS
INSPIRATION FROM NATURE
Brown, K. A.; Kraut, J. Faraday Discuss. 1992, 93, 217-224
Allen, A. E.; MacMillan, D. W. C. Chem. Sci. 2012, 3, 633-658
4
COOPERATIVE CATALYSIS
CLASSIFICATION OF REACTIVITY
Restorative Catalysis
Cascade Catalysis
Cooperative Dual Catalysis
Lee, J. M.; Na, Y.; Han, H.; Chang, S. Chem. Soc. Rev. 2004, 33, 302-312
5
COOPERATIVE CATALYSIS
CLASSIFICATION OF REACTIVITY
Restorative Catalysis
Åkermark, B.; Ljunggren, S. O.; Bäckvall, J. E. J. Am. Chem. Soc. 1979, 101, 2411-2416
Divakaruni, R.; Stille, J. K. J. Am. Chem. Soc. 1978, 100, 1303-1304
Wacker oxidation
Cascade Catalysis
Eschavarren, A. M.; Stille, J. K. J. Am. Chem. Soc. 1987, 109, 5478-5486
Stille-Kelly
coupling
Cooperative Dual Catalysis
Tohda, Y.; Hagihara, N.; Sonogashira, K. Tetrahedron Lett. 1975, 16, 4467-4470
Sonogashira
cross-coupling
Lee, J. M.; Na, Y.; Han, H.; Chang, S. Chem. Soc. Rev. 2004, 33, 302-312
Kürti, L.; Czakó, B. Strategic Applications of Named Reactions in Organic Synthesis; 1st ed.; Elsevier: Burlington, 2005, p. 424, 440, 474
6
COOPERATIVE DUAL CATALYSIS
CATALYST PAIRING
acid-base
Brønsted acid-transition metal
organocatalyst-organocatalyst
Lewis acid-Lewis acid
organocatalyst-transition metal
transition metal-transition metal
7
What’s in a name?
Different names, similar mechanisms
“Cooperative dual catalysis”
Sammis, G. M.; Danjo, H.; Jacobsen, E. N. J. Am. Chem. Soc. 2004, 126, 9928-9929
“Synergistic catalysis”
Simonovich, S. P.; Van Humbeck, J. F.; MacMillan, D. W. C. Chem. Sci. 2012, 3, 58-61
“Contemporaneous dual catalysis”
Luan, X.; Trost, B. M. J. Am. Chem. Soc. 2011, 133, 1706-1709
“Catalyzed catalysis”
Shi, Y.; Roth, K. E.; Ramgren, S. D.; Blum. S. A. J. Am. Chem. Soc. 2009, 131, 18022-18023
8
What’s in a name?
Different names, similar mechanisms
Cooperative dual catalysis
=
Catalyzed catalysis
=
Synergistic catalysis
=
Contemporaneous dual catalysis
9
COOPERATIVE DUAL CATALYSIS
GUIDING PRINCIPLES FOR DEVELOPMENT
substrate-catalyst selectivity
competition with
stoichiometric substrate
catalyst self-quenching
ligand lability
bimetallic complex formation
intermediate affinity
rates of formation
rates of decomposition
Cooperative dual catalysis can be a conceptual framework for reaction design
10
COOPERATIVE DUAL CATALYSIS
INSPIRATION AND EARLY EXAMPLES
Castro-Stephens reaction
Stephens, R. D.; Castro, C. E. J. Org. Chem. 1963, 28, 3313-3315
irreproducible yields
Sonogashira reaction
Tohda, Y.; Hagihara, N.; Sonogashira, K. Tetrahedron Lett. 1975, 16, 4467-4470
•
•
•
•
milder conditions
• near room temperature
• rigorously dry solvent not required
functional group-tolerant
avoids stoichiometric alkynylcuprate
first example of cooperative dual
catalysis
Can this mechanism serve as a model for the design
of other cross-coupling reactions?
11
BETTER TOGETHER: PALLADIUM + COPPER
BEYOND THE SONOGASHIRA REACTION
Rodríguez, N.; Melzer, B.; Linder, C; Deng, G.; Levy, L. M.; Gooβen, L. J. J. Am. Chem. Soc. 2007, 129, 4824-4833
12
BETTER TOGETHER: PALLADIUM + COPPER
COOPERATION FOR BIARYL CROSS-COUPLING
Design by mechanism
Schambach, R. A.; Cohen, T. J. Am. Chem. Soc. 1970, 92, 3189-3190
Nilsson, M. Acta. Chem. Scand. 1966, 20, 423-426
DFT calculations: B3LYP/6-31G* (C, H, N, O, F)
ECP10MDF (Cu)
Influence of ortho coordinating groups
confirmed by experimentation
Thiel, W. R.; Rodríguez, N.; Linder, C.; Melzer, B.; Gooβen, L. J. Adv. Synth. Catal. 2007, 349, 2241-2246
coupling two catalytic processes
Deng, G.; Levy, L. M.; Gooβen, L. J. Science 2006, 313, 662-664
13
BETTER TOGETHER: PALLADIUM + COPPER
COOPERATION FOR BIARYL CROSS-COUPLING
Deng, G.; Levy, L. M.; Gooβen, L. J. Science 2006, 313, 662-664
Expanded…
using Ag2CO3 at lower temperatures
microwave chemistry
aryl triflates
meta or para groups on aryl carboxylate
Linder, C.; Rodríguez, N; Gooβen, L. J. J. Am. Chem. Soc. 2008, 130, 15248-15249
Zimmermann, B.; Linder, C.; Rodríguez, N; Lange, P. P.; Hartung, J.; Gooβen, L. J. Adv. Synth. Catal. 2009, 351, 2667-2674
Linder, C.; Rodríguez, N.; Lange, P. P.; Fromm, A.; Gooβen, L. J. Chem. Commun. 2009, 7173-7175
14
BETTER TOGETHER: PALLADIUM + COPPER
COOPERATION FOR BIARYL CROSS-COUPLING
L = phenanthroline, phosphine, others
X = I, Br, Cl
no reaction with Pd or Cu alone
proposed mechanism
decarboxylation
transmetalation
oxidative addition
anion exchange
reductive
elimination
Deng, G.; Levy, L. M.; Gooβen, L. J. Science 2006, 313, 662-664
15
UNEXPECTED COOPERATION
PALLADIUM-PALLADIUM COOPERATIVE DUAL CATALYSIS
Campeau, L.-C.; Rousseaux, S.; Fagnou, K. J. Am. Chem. Soc. 2005, 127, 18020-18021
expected
major product
SEAr mechanism?
Initial mechanistic study: concerted metalation-deprotonation
DFT analysis: B3LYP/TZVP
B3LYP/DZVP (Pd)
Gorelsky, S. I.; Lapointe, D.; Fagnou, K. J. Am. Chem. Soc. 2008, 130, 10848-10849
16
UNEXPECTED COOPERATION
COOPERATIVE DUAL CATALYSIS IN DIRECT ARYLATION
1
induction period observed
1st order
1
Does cyclometalated
complex do C-H
activation?
2
no induction period
0th order
1/2 order
Tan, Y.; Barrios-Landeros, F.; Hartwig, J. F. J. Am. Chem. Soc. 2012, DOI: 10.1021/ja2122156
17
UNEXPECTED COOPERATION
COOPERATIVE DUAL CATALYSIS IN DIRECT ARYLATION
1
rate does not depend on 1
2
turnover-limiting C-H
activation occurs with 2
rate increases with increasing [2]
calculated ΔG PyO-1 = 33 kcal/mol
ΔG PyO-2 = 25 kcal/mol (experimental 27 kcal/mol)
Is PtBu3 or OAc ligand involved in C-H activation?
1
acetate involved in C-H cleavage
Is transmetalation between 1 and 2 feasible?
cooperative dual
catalysis
1
Tan, Y.; Barrios-Landeros, F.; Hartwig, J. F. J. Am. Chem. Soc. 2012, DOI: 10.1021/ja2122156
18
UNEXPECTED COOPERATION
COOPERATIVE DUAL CATALYSIS IN DIRECT ARYLATION
transmetalation supported
by model study
oxidative addition
acetate involved
in C-H cleavage
1
turnover-limiting
C-H activation
2
reductive elimination
1/2 order
Tan, Y.; Barrios-Landeros, F.; Hartwig, J. F. J. Am. Chem. Soc. 2012, DOI: 10.1021/ja2122156
1st order
19
SUMMARY
COOPERATIVE DUAL CATALYZED CROSS-COUPLING
• Sonogashira is a good mechanistic model
• What is the significance of the Pd/Cu pair?
• Can other metals be substituted for Pd?
• Cooperative dual catalysis can result in…
• Improved reactivity
• Reduced side reactions and reduced catalyst poisoning
• Cooperative dual catalysis cannot always be predicted
• Mechanistic study reveals greater insight into reactions
• Spur development of other transformations
20
COOPERATIVE DUAL CATALYSIS
USING TSUJI-TROST ELECTROPHILES
complexation
decomplexation
oxidative addition
nucleophilic attack
Frost, C. G.; Howart, J.; Williams, J. M. J. Tetrahedron: Asymmetry 1992, 3, 1089-1122
Kürti, L.; Czakó, B. Strategic Applications of Named Reactions in Organic Synthesis; 1st ed.; Elsevier: Burlington, 2005, p. 458
21
COOPERATIVE DUAL CATALYSIS
USING TSUJI-TROST ELECTROPHILES
decomplexation
complexation
oxidative addition
nucleophilic attack
Frost, C. G.; Howart, J.; Williams, J. M. J. Tetrahedron: Asymmetry 1992, 3, 1089-1122
Kürti, L.; Czakó, B. Strategic Applications of Named Reactions in Organic Synthesis; 1st ed.; Elsevier: Burlington, 2005, p. 458
22
COOPERATIVE DUAL CATALYSIS
EARLY EXAMPLES WITH TSUJI-TROST ELECTROPHILES
reaction design
optimized method
additional
substrates
control experiments
Pd has no effect on
enantioselectivity
electron-rich ligands
increase rate of Nu attack
Sawamura, M.; Sudoh, M.; Ito, Y. J. Am. Chem. Soc. 1996, 118, 3309-3310
23
COOPERATIVE DUAL CATALYSIS
EARLY EXAMPLES WITH TSUJI-TROST ELECTROPHILES
oxidative addition
nucleophilic attack
coordination-deprotonation
Does ligand speciation
influence %ee?
decomplexation
Sawamura, M.; Sudoh, M.; Ito, Y. J. Am. Chem. Soc. 1996, 118, 3309-3310
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A GOLDEN OPPORTUNITY
NOVEL REACTIVITY WITH GOLD AND PALLADIUM
reaction design
optimized conditions
Is the mechanistic design truly operative?
Shi, Y.; Roth, K. E.; Ramgren, S. D.; Blum. S. A. J. Am. Chem. Soc. 2009, 131, 18022-18023
25
A GOLDEN OPPORTUNITY
PROPOSED MECHANISM
Observed by 1H NMR spectroscopy
oxidative addition
ID by MS
and competition
studies
reductive
elimination
Saturation kinetics in
substrate suggest
pre-equilibrium
transmetalation
Shi, Y.; Roth, K. E.; Ramgren, S. D.; Blum. S. A. J. Am. Chem. Soc. 2009, 131, 18022-18023
26
COOPERATIVE DUAL CATALYSIS
OVERCOMING CHALLENGES IN SYNTHETIC CHEMISTRY
mechanistic hypothesis
Meyer-Schuster
affinity of intermediates for each
other vs. affinity for substrate
optimized conditions
Luan, X.; Trost, B. M. J. Am. Chem. Soc. 2011, 133, 1706-1709
Luan, X.; Miller, Y.; Trost, B. M. J. Am. Chem. Soc. 2011, 133, 12824-12833
27
IS IT REALLY COOPERATIVE CATALYSIS?
QUALITATIVE EXPERIMENTS
system sensitive to catalyst
ratios!
rates matter!
Luan, X.; Trost, B. M. J. Am. Chem. Soc. 2011, 133, 1706-1709
Luan, X.; Miller, Y.; Trost, B. M. J. Am. Chem. Soc. 2011, 133, 12824-12833
28
IS IT REALLY COOPERATIVE CATALYSIS?
QUALITATIVE EXPERIMENTS
Is sequential catalysis operating?
Luan, X.; Trost, B. M. J. Am. Chem. Soc. 2011, 133, 1706-1709
Luan, X.; Miller, Y.; Trost, B. M. J. Am. Chem. Soc. 2011, 133, 12824-12833
Is palladium necessary?
29
PROPOSED MECHANISM
L1 = OSiPh3
L2 =
desired product
rearrangement
side
product
Luan, X.; Trost, B. M. J. Am. Chem. Soc. 2011, 133, 1706-1709
Luan, X.; Miller, Y.; Trost, B. M. J. Am. Chem. Soc. 2011, 133, 12824-12833
oxidative addition
side
product
30
SUMMARY
COOPERATIVE DUAL CATALYZED ALLYLATIONS
• Judicious pairing of electrophile and nucleophile required
• Need reliable intermediates
• Tsuji-Trost
• Cooperative dual catalysis provides:
• Improved reactivity
• Novel reactivity
• Reduced side reactions and reduced catalyst poisoning
• Qualitative mechanistic studies provide insight
• Kinetics and stoichiometric studies will expand scope of
reactivity
31
COOPERATIVE DUAL CATALYSIS
GUIDING PRINCIPLES AND CONCLUSIONS
substrate-catalyst selectivity
competition with
stoichiometric substrate
catalyst self-quenching
ligand lability
bimetallic complex formation
intermediate affinity
rates of formation
rate of decomposition
Ideal reaction: atom economical, few steps, readily available materials, selective
32
THE FUTURE OF THE FIELD
• Rigorous mechanistic studies
• Kinetics
•
Spectroscopy
• Stoichiometric studies
• Control experiments
• Expansion of methodology to other mechanistically welldefined systems
• Using reliable intermediates
• Broadening cooperative Tsuji-Trost chemistry
•
•
Expanding scope of nucleophiles
Tuning regioselectivity with ligands
• Using cooperative dual catalysis as conceptual framework
for reaction design
• Beyond palladium
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ACKNOWLEDGEMENTS
Prof. Shannon Stahl
Kat Myhre
Stahl group
Landis group
Practice Talk Attendees:
Colin Anson
Jackie Brown
Megan Cismesia
Tianning Diao
David Mannel
Jared Rigoli
Dr. James Gerken
Sara Moyer
Alison Suess
Jodie Greene
Alicia Phelps
Dian Wang
Dr. Wan Pyo Hong
Dr. Adam Powell
Adam Weinstein
Dr. Jessica Hoover
Dr. Doris Pun
Paul White
Andrei Iosub
Dr. Ali Rahimi
Dr. Changwu Zheng
Jon Jaworski
Joanne Redford
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