Synthesis of novel polycyclic aromatic hydrocarbons by transannular cyclization of dehydrobenzoannulenes Tobe Laboratory M1 Yamane Hiroshi ~Introduction~ Polycyclic Aromatic Hydrocarbons (PAH) PAH・・・多環状芳香族化合物 picene K - Doped 20K Superconducting materials Kubozono, Y. et al. Nature, 2010, 464, 76-79. 9,9’-bifluorenylidene Electron Acceptors of Lightweight Organic devices Wudl, F. et al. Angew. Chem. Int. Ed. 2009, 49, 532-536. ~Introduction~ Reactivity of alkyne πbond πbond σbond Bond energy : σbond > πbond(1) >πbond(2) (kJ/mol) 369 268 202 Alkyne has high reactivity ~Introduction~ Tandem Cyclization Reaction by Electrophile Tandem Cyclization・・・連続環化 Lutz, V. et al. Angew. Chem. Int. Ed. 2003, 42, 5757−5760. Scheme 1. Tandem cyclization reaction by electrophilic Low selectivity and low yield 4 ~Purpose of my reserch~ Motivation Noncyclic compounds Distance between acetylenes is loose ・Low selectivity ・Low yield 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 Scheme 2. Transannular cyclization of cyclic compounds by several ways Three-dimentional model of 1 Figure 1. Cariculated three-dimentional model of 1 (calculations are based on B3LYP/6-31G*) Prediction of reaction of 1 with nucleophile Scheme 3. Predicted cyclization reaction of 1 Synthesis route of 1 Sceme 4. Synthesis route of 1 Prediction of reaction of 7 Scheme 5. Reaction of 7 passed through benzyne intermediate Computational results for [2+4] diyne-yne cycloaddition ＋ TS1 +36.5 0.0 kcal/mol High potential Energy E -51.4 reactive coordinate Aida A. et al. J. Org. Chem. 2011, 76, 9320-9328. Property of benzyne Overlap of each p orbital is little Electrons are localized benzene benzyne sp2 orbitals are conjugated More destabilization stabilization Scheme 6. Diels-Alder reaction of benzyne and furan Future work 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.
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