Trimethylenemethane TMM

1
Trimethylenemethane (TMM)
2
Two reactions of TMM diyls atom transfer
cyclization and cycloaddition
Arup Maiti, James B. Gerken, Mo Masjedizadeh,
Yvette Mimieux, J. Org. Chem., 2004, 69(25),
8574-8582.
3
Cycloaddition in synthesis
ATC in synthesis
Luc Van Hijfte, J. Petersen, K. Moeller, J. Org.
Chem. 1987, 52, 4647-4661.
Georgia Law Carroll, Amy Kim Allan, Michael
Schwaebe, Org. Lett. 2000, 2(16), 2531-2534.
4
Cycloaddition in synthesis
ATC in synthesis
Luc Van Hijfte, J. Petersen, K. Moeller, J. Org.
Chem. 1987, 52, 4647-4661.
Georgia Law Carroll, Amy Kim Allan, Michael
Schwaebe, Org. Lett. 2000, 2(16), 2531-2534.
5
Quantum calculations as an aide ( DFT )
6
Quantum calculations as an aide ( DFT )
7
Quantum calculations as an aide ( DFT )
8
Quantum calculations as an aide ( DFT )
TS mid-way
Early TS with a substantially lower Ea a
more stable interme- diate forms its
stability can be correlated with the
reduction in Ea (BEP)
9
(No Transcript)
10
(No Transcript)
11
Consistent with the Hammond postulate the
Bell-Evans-Polanyi principle
12
GLOSSARY OF TERMS USED IN PHYSICAL ORGANIC
CHEMISTRY Hammond postulate If two states, as
for example, a transition state and an
unstable intermediate, occur consecutively during
a reaction process and have nearly the same
energy content, their interconversion
will involve only a small reorganization of the
molecular structures. That is, along a reaction
coordinate, species with similar energies have
similar structures. we
can relate Ea and DH. Exothermic
reaction TS resembles starting structure
endothermic reaction TS resembles
products JACS, 1955
(77) p. 334 Ex - free radical halogenation of
hydrocarbons
13
GLOSSARY OF TERMS USED IN PHYSICAL ORGANIC
CHEMISTRY Hammond postulate If two states, as
for example, a transition state and an
unstable intermediate, occur consecutively during
a reaction process and have nearly the same
energy content, their interconversion
will involve only a small reorganization of the
molecular structures. That is, along a reaction
coordinate, species with similar energies have
similar structures. we
can relate Ea and DH. Exothermic
reaction TS resembles starting structure
endothermic reaction TS resembles
products JACS, 1955
(77) p. 334 Ex - free radical halogenation of
hydrocarbons Bell-Evans-Polanyi principle The
linear relation between energy of activation
(Ea) and enthalpy of reaction (Hr) sometimes
observed within a series of closely related
reactions. Ea
A ?Hr