Tobe Laboratory M1 Yamane Hiroshi Synthesis of novel polycyclic aromatic hydrocarbons by...
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Tobe LaboratoryM1 Yamane Hiroshi
Synthesis of novel polycyclic aromatic hydrocarbons by transannular cyclization of
dehydrobenzoannulenes
Polycyclic Aromatic Hydrocarbons (PAH)PAH ・・・多環状芳香族化合物
picene
9,9’-bifluorenylidene
Superconducting materials
K - Doped
20K Electron Acceptors ofLightweight Organic devices
Kubozono, Y. et al. Nature, 2010, 464, 76-79. Wudl, F. et al. Angew. Chem. Int. Ed. 2009, 49, 532-536.
~Introduction~
Reactivity of alkyne
πbond σbond
πbond
Bond energy : σbond > πbond(1) >πbond(2) (kJ/mol) 369 268 202
Alkyne has high reactivity
~Introduction~
Tandem Cyclization Reaction by Electrophile
Scheme 1. Tandem cyclization reaction by electrophilic
Br+
Br Br
Br
Br -
Br
Br
Br
Br
Br
b
a
b
a
Lutz, V. et al. Angew. Chem. Int. Ed. 2003, 42, 5757−5760.
Tandem Cyclization ・・・連続環化
4
Low selectivity and low yield
~Introduction~
Motivation
・ Low selectivity・ Low yield
Noncyclic compounds Distance between acetylenes is loose
Cyclic compounds Distance between acetylenes is fixed
・ Improvement of selectivity・ Improvement of yield・ Induction of spontaneous reaction
~Purpose of my reserch~
Transannular cyclization for cyclic compounds
OC4H9
OC4H9
C4H9O
C4H9O
1. n-BuLi2. BuI
THF
Bu
BuC4H9O
C4H9O
OC4H9
OC4H9
44%
Br
Br
Br
Br
Br2
CHCl30 °C r.t.
BuBu
1. n-BuLi, THF, -78 °C2. H2O
59%
32%
Scheme 2. Transannular cyclization of cyclic compounds by several ways
~Purpose of my reserch~
3.15 Å 3.17 Å
Three-dimentional model of 1
1
Figure 1. Cariculated three-dimentional model of 1 (calculations are based on B3LYP/6-31G*)
Prediction of reaction of 1 with nucleophile
Bu
Bu Bu Bu
Bu
H+
H1 2
Scheme 3. Predicted cyclization reaction of 1
Synthesis route of 1
n-BuLi, t-BuOK
hexane
Li
Li
B(OiPr)3B(OH)2
(HO)2B
OHC
CHO
HH
Pd(PPh3)2Cl2, CuI, I2
THF, (i-Pr)2NH
1
3 4 5 6
8
ether
CHOBr
PPh3, CBr4, Zn
CH2Cl2
LDA
THF
Pd(PPh3)4, K2CO3
Br
Br
Br
Br
toluene, H2O, ethanol
7
9Sceme 4. Synthesis route of 1
Prediction of reaction of 7
9
HH
Pd(PPh3)2Cl2, CuI, I2
THF, (i-Pr)2NH
7
2H+
1 benzyne intermediate
Scheme 5. Reaction of 7 passed through benzyne intermediate
Computational results for [2+4] diyne-yne cycloaddition
+
0.0 kcal/mol
-51.4
E
TS1+36.5
High potential Energy
reactive coordinate
Aida A. et al. J. Org. Chem. 2011, 76, 9320-9328.
Property of benzyne
benzene benzyne
O
O
O
Overlap of each p orbital is little
sp2 orbitals are conjugated
Electrons are localized
Scheme 6. Diels-Alder reaction of benzyne and furan
More destabilization
stabilization
Future work
9
HH
Pd(PPh3)2Cl2, CuI, I2
THF, (i-Pr)2NH
7
2H+
O
O
Scheme 8. Trapping of benzyne intermediate by furan
Conclusion
• Acetylene-integrated 1 is designed.
• After the synthesis of 1, 7 is considered generated via benzyne intermediates.
• I will confirm the presence of a benzyne intermediate by furan.