Investigating Substrate Reactivity in Hydroacylation Reactions with Rhodium Catalysts Geno Schneider Dr. Joe Scanlon Ripon College
Investigating Substrate
Reactivity in Hydroacylation
Reactions with Rhodium
Catalysts
Geno Schneider
Dr. Joe Scanlon
Ripon College
Outline Background
Hydroacylation
Previous Studies
Chirality
Potential Energy Surfaces
Results
Conclusions
Ongoing and Future Research
Acknowledgments
References
Hydroacylation Alkene and aldehyde react to form a new carbon-
carbon bond
Intramolecular hydroacylation requires a catalyst
Previous Research Stanley Group at Iowa State
Found unique substitution effects and high
enantioselectivity
Previous Research Tested many substituents and ligands
Found as a backbone in narcotics
Previous Research Dr Sargent et. al
Computational Study on simple system
Brian Schumacher and Dr. Joe Scanlon
computationally studied Dr. Stanley's system
Mechanism Changes from Sargent
Additional Intermediate found
Chirality
Potential Energy Surfaces Depict relative energies
Reaction alternates between intermediates(local
minima) and transition states(local maxima).
Determine mechanisms of reactions
-65
-55
-45
-35
-25
-15
-5
De
lta
H (
kcal
/mo
l)
Reaction Coordinate
PES
Mechanism
Dr. Sargent Recreated Sargent’s system with two methods
H-coordination Intermediate was found in both cases
0
10
20
30
De
lta
E (k
cal/
mo
l)
Reaction Coordinate
PES
M06L
B3LYP
Sargent
6-HcoordTS
I6
Hcoord
Hcoord-7aTS
I7a
Sargent’s
TS
Enantioselective Reaction Intramolecular Hydroacylation catalyzed by
[Rh(BINAP)]
Enantioselectivity
Different side of alkene coordinating to Rh, allowing for R or S
enantiomers to be formed.
Pathway of R vs S Enantiomers
O
R1
R2
H
O
R1 R2
LRh(I)
H
H
R1 R2
LRh(I)
OO
R1 R2
LRh(I)
H
O
H
R2
LRh(I)
R1
O
H
R2
LRh(I)
R1
O
H
R2
R1
O
H
R2
R1
O
R1
R2
H
O
R1 R2
LRh(I)
H
H
R1 R2
LRh(I)
OO
R1 R2
LRh(I)
H
O
H
R2
LRh(I)
R1
O
H
R2
LRh(I)
R1
O
H
R2
R1
O
H
R2
R1
R Enantiomer S Enantiomer
-65
-55
-45
-35
-25
-15
-5
5
De
lta
H (
kcal
/mo
l)
Reaction Coordinate
PES
S Enantiomer
R Enantiomer
I2
SM
I1
TS1
I3
TS2
TS3
I4
TS4
I5
TS5
ΔH kcal/mol
TS1 TS2 TS3 TS4 TS5
R-S 2.9 11.1 -3.1 -0.5 3.0
3.90A
2.52A
S Enantiomer, Transition State 2
2.13A2.70A
R Enantiomer, Transition State 2
Distance to catalyst phenol rings
S Enantiomer, Transition State 2
Dihedral Angle=6.65
R Enantiomer, Transition State 2
Dihedral Angle= -16.40
Dihedral angle
Cyclopentene and
Cyclohexene
-25
-15
-5
5D
elt
a H
(kc
al/m
ol)
Reaction Coordinate
PES
Cyclohexane
Cyclopentane
I2
SM
I1
TS1
I3
TS2
TS3
I4
TS4
I5
TS5
ΔH kcal/mol
TS1 TS2 TS3 TS4 TS5
CH-CP 1.7 1.4 4.1 NA -7.2
Future Work Finish Cyclopentene pathway.
Analyze geometry to explain differences in energy.
Acknowledgements MU3C Cluster
National Science Foundation
Knop Scholarship Fund
Ripon College Chemistry Department
Dr. Joe Scanlon
References1. Beletskiy, E. V.; Sudheer, Ch.; Douglas, C. J. Cooperative Catalysis Approach to
Intramolecular Hydroacylation. J. Org. Chem, 2012, 77, 5884-5893.
2. Ghosh, A.; Stanley, L. M. Enantioselective hydroacylation of N-vinylindole-2-
carboxaldehydes. Chemical Communication 2014, 50, 2765-2768.
3. Dempsey Hyatt, I. F.; Anderson, H. K.; Morehead, Jr. A. T.; Sargent, A. L. Mechanism of
Rhodium-Catalyzed Intromolecular Hydroacylation: A Computational Study. Organometallics
2007, 27, 135-147.
4. Pawley, R. J.; Huertos, M. A.; Lloyd-Jones, G. C.; Weller, A. S.; Willis, M. C. Intermolecular
Alkyne Hydroacylation. Mechanistic Insight from the Isolation of the Vinyl Intermediate That
Precedes Reductive Elimination. Organometallics 2012, 31, 5650-5659.
5. Gao, J.; Wang, F.; Meng, Q.; Li, M. Density Functional Computations of Rh(I)-Catalyzed
Hydroacylation of Ethene or Ethyne. Journal of Theoretical and Computational Chemistry,
2008, 7, 1041-1053.