Synthesis, Mechanism, and Properties of Cyclopenta-fused Polycyclic Aromatic Hydrocarbons. Chaolumen. Introduction

Transcription

1 March 22, 2018 Synthesis, Mechanism, and Properties of Cyclopenta-fused Polycyclic Aromatic Hydrocarbons Reaxys Prize Club Symposium in Japan 2018 Chaolumen Institute for Chemical Research, Kyoto University Graduate School of Science, Nagoya University Introduction Cyclopenta-fused Polycyclic Aromatic Hydrocarbons (Segments of Fullerenes ) Fullerene C 60 Pyracylene Fullerene C 70 Cyclopent[hi]aceanthrylene Review: Plunkett, K. N. Synlett 2013, 24, Good electron accepting abilities Unique photophysical properties Chemical reactivitiy, etc.

2 Cyclopenta-Fused Polycyclic Aromatic Hydrocarbons Representative Examples Electron Acceptor Ambipolar Material Electron Acceptor Electron Acceptor Chen, C.-T. et al., RSC Adv. 2015, 5, Wudl, F. et al., Chem. Eur. J. 2011, 17, Transition Metal-Catalyzed Cross-Coupling Plunkett, K. N. et al., J. Am. Chem. Soc. 2012, 134, Plunkett, K. N. et al., Polym. Chem. 2016, 7, 292 Only a few examples Wudl, F. et al., Chem. Eur. J. 2011, 17, Plunkett, K. N. et al., J. Am. Chem. Soc. 2012, 134, Limited synthetic methodologies The Scholl Reaction Efficient for formation of hexagonal ring Mechanism is under discussion. Müllen, K. et al., Chem. Eur. J. 1998, 4, Reported Mechanism for the Scholl Reaction Radical cation C-C bond formation Rathore, R. et al., J. Org. Chem. 2010, 75, 4748.

3 Selective Formation of Pentagonal Ring Müllen, K. et al., J. Mater. Chem. 2006, 16, Gourdon, A. et al., Tetrahedron 2012, 68, Gourdon, A. et al., New J. Chem. 2015, 39, This unique selectivity cannot be explain by the current mechanism. Reported Mechanism for the Scholl Reaction Radical cation C-C bond formation Rathore, R. et al., J. Org. Chem. 2010, 75, Topic 1. Synthesis and Properties of Tetrabenzo-fused Pyracylene - Rational synthetic design - Efficient synthesis - Unique reactivity - Distinct emission Chaolumen; Murata, M.; Sugano, Y.; Wakamiya, A.; Murata, Y. Angew. Chem., Int. Ed. 2015, 54, Topic 2. Mechanistic Study of the Scholl Reaction - π-extension - Unsymmetric cyclization - Dication pathway Chaolumen; Murata, M.; Wakamiya, A.; Murata, Y. Angew. Chem., Int. Ed. 2017, 56, Hot Paper

4 Topic 1. Synthesis and Properties of Tetrabenzo-fused Pyracylene - Rational synthetic design - Efficient synthesis - Unique reactivity - Distinct emission Chaolumen; Murata, M.; Sugano, Y.; Wakamiya, A.; Murata, Y. Angew. Chem., Int. Ed. 2015, 54, Topic 2. Mechanistic Study of the Scholl Reaction - π-extension - Unsymmetric cyclization - Dication pathway Chaolumen; Murata, M.; Wakamiya, A.; Murata, Y. Angew. Chem., Int. Ed. 2017, 56, Hot Paper π-extension of Pyracylene Liebman, J. F. et al., J. Am. Chem. Soc. 2002, 124, Recently Reported Synthesis of TBP Schneider, J. J. et al., Eur. J. Org. Chem. 2016, 569.

5 not observed Schneider, J. J. et al., Eur. J. Org. Chem. 2016, 569. Low lying LUMO

6 Stepwise and selective 1,4 addition Scott, L. T. et al., J. Org. Chem. 2008, 73, 88. Wudl, F. et al., Chem. Eur. J. 2011, 17, π-extended triptycene

7 λ λ λ λ λ λ λ λ λ High quantum yield λ λ λ λ λ λ λ λ λ λ λ λ abs 376 nm λ em 383 nm λ em 441, 465 nm

8 Curved λ Dimer structure Planar λ No dimer structure Topic 1. Synthesis and Properties of Tetrabenzo-fused Pyracylene - Rational synthetic design - Efficient synthesis - Unique reactivity - Distinct emission Chaolumen; Murata, M.; Sugano, Y.; Wakamiya, A.; Murata, Y. Angew. Chem., Int. Ed. 2015, 54, Topic 2. Mechanistic Study of the Scholl Reaction - π-extension - Unsymmetric cyclization - Dication pathway Chaolumen; Murata, M.; Wakamiya, A.; Murata, Y. Angew. Chem., Int. Ed. 2017, 56, Hot Paper

9 Cyclization of Dinaphthyltetracene Chaolumen; Murata, M.; Sugano, Y.; Wakamiya, A.; Murata, Y. Angew. Chem., Int. Ed. 2015, 54, Possible Products M06-2X/6-31G** Cyclization of Dinaphthyltetracene Mono-cyclized product was not observed. Possible Products M06-2X/6-31G**

10 Rathore, R. et al., J. Org. Chem. 2010, 75, DDQ/MeSO 3 H as Oxidant Radical cation λ Radical Cation of Tetracene Radical cation λ Kimura, K. J. Phys. Chem. 1971, 75, 1768.

11 Rathore, R. et al., J. Org. Chem. 2010, 75, High barriers Unlikely to proceed at RT Radical cation pathway Rathore, R. et al., J. Org. Chem. 2010, 75, 4748.

12 The First Cyclization Kinetically favored Low barriers The Second Cyclization PCM(DCM)-M06-2X/6-31G**//M06-2X/6-31G** high barriers TS for pentagon in the first cyclization (12.8 kcal/mol) Kinetically and thermodynamically favored

13 Efficient Synthesis and Unique Reactivity (1) n-buli (2) n-bui Curved Planar Chaolumen; Murata, M.; Sugano, Y.; Wakamiya, A.; Murata, Y. Angew. Chem., Int. Ed. 2015, 54, Unsymmetric cyclization through dication pathway Pentagon Preferred Hexagon Preferred Chaolumen; Murata, M.; Wakamiya, A.; Murata, Y. Angew. Chem., Int. Ed. 2017, 56, Hot Paper