Straightforward Synthesis of Novel Acene-Based Aryne Precursors

Dedicated to Prof. K. Peter C. Vollhardt

Abstract

Large polycyclic o-(trimethylsilyl)aryl triflates are easily obtained by reaction of commercially available bisaryne precursors with cyclopentadienones. The transformation involves controlled generation of one of the aryne functionalities, trapping by Diels–Alder reaction with a dienone, and chelotropic extrusion of CO. The newly synthesized triflates are precursors of acene-based arynes, including a didehydropentacene.

Key words

arynes - polycyclic aromatic hydrocarbons - acenes - Diels–Alder reaction - cycloadditions

• References and Notes


General reviews on aryne chemistry:
• 1a Hoffmann RW. Dehydrobenzene and Cycloalkynes . Academic Press; New York: 1967
• 1b Hart H. The Chemistry of Triple-Bonded Functional Groups . In Arynes and Heteroarynes . Patai S, Rappoport Z. Wiley; Chichester: 1994. Suppl. C2 1017
• 1c Pellisier H, Santelli M. Tetrahedron 2003; 59: 701
• 1d Sanz R. Org. Prep. Proced. Int. 2008; 40: 215
• 2 Kitamura T. Aust. J. Chem. 2010; 98: 987
• 3 Himeshima Y, Sonoda T, Kobayashi H. Chem. Lett. 1983; 1211

Representative metal-catalyzed transformations involving arynes:
• 4a Peña D, Escudero S, Pérez D, Guitián E, Castedo L. Angew. Chem. Int. Ed. 1998; 37: 2659
• 4b Peña D, Pérez D, Guitián E, Castedo L. J. Am. Chem. Soc. 1999; 121: 5827
• 4c Yokinawa E, Yamamoto Y. Angew. Chem. Int. Ed. 2000; 39: 173
• 4d Peña D, Pérez D, Guitián E. Palladium-Catalyzed Cycloaddition Reactions of Arynes, In Palladium in Organic Synthesis . Vol. 14. Tsuji J. Springer; Weinheim: 2005: 109
• 4e Liu Z, Larock RC. J. Org. Chem. 2007; 72: 223
• 4f Yoshida H, Ohshita J, Kunai A. Bull. Chem. Soc. Jpn. 2010; 83: 199
• 4g Worlikar SA, Larock RC. Current. Org. React. 2011; 15: 3214

Representative novel metal-free transformations:
• 5a Peña D, Pérez D, Guitián E. Angew. Chem. Int. Ed. 2006; 45: 3579
• 5b Bhunia A, Yetra SR, Biju AT. Chem. Soc. Rev. 2012; 41: 3140
• 5c Bhunia A, Biju AT. Synlett 2014; 25: 608
• 5d Criado A, Vilas-Varela M, Cobas A, Pérez D, Peña D, Guitián E. J. Org. Chem. 2013; 78: 12637
• 5e Dubrovskiy AV, Markina NA, Larock RC. Org. Biomol. Chem. 2013; 11: 191
• 6a Tadross PM, Stoltz BM. Chem. Rev. 2012; 112: 3550
• 6b Gampe CM, Carreira EM. Angew. Chem. Int. Ed. 2012; 51: 3766
• 7a Pérez D, Peña D, Guitián E. Eur. J. Org. Chem. 2013; 5981
• 7b Li J, Zhang Q. Synlett 2013; 24: 686
• 8 Peña D, Cobas A, Pérez D, Guitián E, Castedo L. Synthesis 2002; 1454
• 9 Romero C, Peña D, Pérez D, Guitián E. Chem. Eur. J. 2006; 12: 5677
• 10 Iglesias B, Cobas A, Pérez D, Guitián E, Vollhardt KP. C. Org. Lett. 2004; 6: 3557
• 11 Sygula A, Sygula R, Kobryn L. Org. Lett. 2008; 10: 3927
• 12 Duong HM, Bendikov M, Steiger D, Zhang Q, Sonmez G, Yamada J, Wudl F. Org. Lett. 2003; 5: 4433
• 13 Kitamura C, Abe Y, Ohara T, Yoneda A, Kawase T, Kobayashi T, Naito H, Komatsu T. Chem. Eur. J. 2010; 16: 890
• 14 Alonso JM, Díaz-Álvarez AE, Criado A, Peña D, Pérez D, Guitián E. Angew. Chem. Int. Ed. 2012; 51: 173
• 15 Wooi GY, White JM. Org. Biomol. Chem. 2005; 3: 972
• 16 General Procedure To a solution of bisaryne precursor 1 or 2 and cyclopentadienone 4, 10, or 11 (110 mol%), in 2:1 MeCN–CH₂Cl₂, finely powdered anhydrous CsF (120 mol%) was added, and the mixture was stirred at 50 °C under argon atmosphere for 12 h. The solvent was evaporated under reduced pressure, and the resulting mixture was purified by column chromatography (SiO₂, hexanes–CH₂Cl₂) to isolate the corresponding o-(trimethylsilyl)aryl triflate. In some experiments, the intermediate Diels–Alder adduct (e.g., 9) was detected in other fractions eluted from the column, which were collected, concentrated under vacuum, dissolved in tetrachloroethane, and refluxed for 12 h. Evaporation of the solvent under vacuum and column chromatography (SiO₂, hexanes–CH₂Cl₂) of the residue afforded an additional portion of o-(trimethylsilyl)aryl triflate. 9,14-Diphenyl-12-(trimethylsilyl)benzo[f]tetraphen-11-yl Trifluoromethanesulfonate (3) Reaction of 1,3-diphenyl-2H-cyclopenta[l]phenanthren-2-one (4, 243 mg, 0.637 mmol), 2,5-bis(trimethylsilyl)-1,4-phenylene bis(trifluoromethanesulfonate) (1, 300 mg, 0.579 mmol), and CsF (105 mg, 0.695 mmol) in MeCN–CH₂Cl₂ (2:1; 9 mL) afforded 3 (218 mg, 58%) as a greenish solid; mp 219–221 °C. ¹H NMR (250 MHZ, CDCl₃): δ = 8.29 (d, J = 7.3 Hz, 2 H), 8.13 (s, 1 H), 7.85 (s, 1 H), 7.59 (d, J = 8.5 Hz, 2 H), 7.54 (m, 5 H), 7.54 (m, 5 H), 7.41–7.36 (m, 2 H), 7.04–6.98 (m, 2 H), 0.33 (s, 9 H) ppm. ¹³C NMR (63 MHz, CDCl₃): δ = 152.6 (C), 140.9 (C), 140.5 (C), 136.8 (CH), 135.4 (C), 135.2 (C), 132.7 (C), 132.3 (2 CH), 132.2 (C), 132.1 (2 CH), 132.1 (C), 131.9 (C), 130.8 (C), 130.6 (C), 130.55 (C), 130.50 (CH), 130.4 (CH), 129.8 (C), 129.3 (C), 129.1 (2 CH), 129.0 (2 CH), 128.0 (CH), 127.9 (CH), 127.3 (CH), 127.2 (CH), 125.9 (2 CH), 123.3 (2 CH), 115.7 (CH), –0.8 (3 CH₃) ppm. MS (EI): m/z (%) = 650 (30). HRMS (EI): m/z calcd for C₃₈H₂₉F₃O₃SSi: 650.1559; found: 650.1563. 5,6,7,8-Tetraphenyl-3-(trimethylsilyl)naphthalen-2-yl Trifluoromethanesulfonate (12) Reaction of 2,3,4,5-tetraphenylcyclopenta-2,4-dien-1-one (10, 329 mg, 0.858 mmol), 2,5-bis(trimethylsilyl)-1,4-phenylene bis(trifluoromethanesulfonate) (1, 404 mg, 0.780 mmol), and CsF (142 mg, 0.936 mmol) in MeCN–CH₂Cl₂ (2:1; 11 mL) afforded 12 (305 mg, 60%) as a white solid; mp 249–251 °C. ¹H NMR (300 MHZ, CDCl₃): δ = 7.89 (s, 1 H), 7.59 (s, 1 H), 7.32–7.20 (m, 10 H), 6.92–6.87 (m, 10 H), 0.30 (s, 9 H) ppm. ¹³C NMR (75 MHz, CDCl₃): δ = 152.8 (C), 140.7 (C), 139.9 (4C), 138.7 (2 C), 138.5 (C), 138.3 (C), 136.9 (CH), 133.4 (C), 131.1 (3 CH), 131.1 (4 CH), 130.9 (2 CH), 130.5 (C), 127.7 (2 CH), 127.6 (2 CH), 126.9 (CH), 126.7 (4 CH), 125.7 (CH), 125.6 (CH), 118.4 (q, J = 320 Hz, CF₃), 116.3 (CH), –0.9 (3 CH₃) ppm. MS (EI): m/z (%) = 652.3 (70) [M⁺], 504.3 (14), 293.3 (41), 147.1 (43). HRMS (EI): m/z calcd for C₃₈H₃₁F₃O₃SSi: 652.1715; found: 652.1713. 9,14-Diphenyl-12-(trimethylsilyl)dibenzo[de,qr]tetracen-11-yl Trifluoromethanesulfonate (13) Reaction of 9,11-diphenyl-10H-cyclopenta[e]pyren-10-one (11, 100 mg, 0.246 mmol), 2,5-bis(trimethylsilyl)-1,4-phenylene bis(trifluoromethanesulfonate) (1, 116 mg, 0.224 mmol), and CsF (41 mg, 0.269 mmol) in MeCN–CH₂Cl₂ (2:1; 9 mL) afforded 13 (66 mg, 40%) as a yellow solid; mp 279–281 °C. ¹H NMR (500 MHZ, CDCl₃): δ = 8.11 (s, 1 H), 7.90–7.85 (m, 6 H), 7.82 (s, 1 H), 7.56–7.48 (m, 10 H), 7.35 (td, J = 7.9, 2.2 Hz, 2 H), 0.32 (s, 9 H) ppm. ¹³C NMR (126 MHz, CDCl₃): δ = 153.0 (C), 141.7 (C), 141.4 (C), 137.3 (CH), 136.9 (C), 136.6 (C), 133.2 (C), 132.4 (2 CH), 132.2 (2 CH), 131.0 (C), 131.0 (C), 130.99 (C) 130.97 (C), 130.3 (C), 130.2 (C), 130.1 (C), 129.9 (C), 129.5 (2 CH), 129.4 (2 CH), 129.1 (CH), 129.0 (CH), 128.2 (CH), 128.1 (CH), 127.1 (CH), 127.1 (CH), 126.6 (CH), 126.4 (CH), 126.2 (C), 126.1 (C), 125.1 (CH), 125.0 (CH), 118.5 (q, J = 325 Hz, CF₃), 116.1 (CH), –0.6 (3 CH₃) ppm. MS (EI): m/z (%) = 674 (100) [M⁺], 541 (53), 448 (16). 5,6,7,8-Tetraphenyl-3-(trimethylsilyl)anthracen-2-yl Trifluoromethanesulfonate (17) Reaction of 2,3,4,5-tetraphenylcyclopenta-2,4-dien-1-one (10, 126 mg, 0.329 mmol), 3,6-bis(trimethylsilyl)-naphthalene-2,7-diyl bis(trifluoromethanesulfonate) (2, 115 mg, 0.299 mmol), and CsF (55 mg, 0.359 mmol) in MeCN–CH₂Cl₂ (2:1; 9 mL) afforded 17 (84 mg, 40%) as a white solid; mp 223–225 °C. ¹H NMR (300 MHZ, CDCl₃): δ = 8.27 (s, 1 H), 8.22 (s, 1 H), 8.04 (s, 1 H), 7.82 (s, 1 H), 7.39–7.21 (m, 10 H), 7.01–6.78 (m, 10 H), 0.43 (s, 9 H) ppm. ¹³C NMR (75 MHz, CDCl₃): δ = 152.4 (C), 140.5 (2 C), 139.91 (C), 139.59 (C), 139.52 (C), 139.4 (C), 139.0 (CH), 138.6 (C), 138.3 (C), 132.1 (C), 131.7 (C), 131.6 (CH), 131.6 (CH), 131.4 (CH), 129.6 (C), 128.1 (CH), 128.0 (CH), 127.0 (CH), 126.9 (CH), 126.9 (CH), 126.8 (CH), 126.4 (CH), 125.7 (CH), 116.2 (CH), –0.4 (3 CH₃) ppm. MS (MALDI-TOF): m/z = 702 [M⁺]. 9,16-Diphenyl-13-(trimethylsilyl)dibenzo[a,c]tetracen-12-yl Trifluoromethanesulfonate (18) Reaction of 1,3-diphenyl-2H-cyclopenta[l]phenanthren-2-one (4, 148 mg, 0.388 mmol), 3,6-bis(trimethylsilyl)-naphthalene-2,7-diyl bis(trifluoromethanesulfonate) (2, 200 mg, 0.353 mmol), and CsF (65 mg, 0.424 mmol) in MeCN–CH₂Cl₂ (2:1; 9 mL) afforded 18 (50 mg, 21%) as a yellow solid. ¹H NMR (500 MHZ, CDCl₃): δ = 8.51 (s, 1 H), 8.46 (s, 1 H), 8.18 (d, J = 7.9 Hz, 2 H), 8.05 (s, 1 H), 7.84 (s, 1 H), 7.66–7.54 (m, 10 H), 7.42 (t, J = 8.0 Hz, 2 H), 7.32 (t, J = 7.5 Hz, 2 H), 6.95 (t, J = 7.7 Hz, 2 H), 0.43 (s, 9 H) ppm. ¹³C NMR (126 MHz, CDCl₃): δ = 152.4 (C), 141.6 (2 C), 141.5 (2 C), 139.0 (CH), 135.4 (C), 135.0 (C), 133.0 (2 CH), 133.0 (2 CH), 132.6 (C), 132.6 (C), 131.8 (C), 131.5 (C), 131.5 (C), 131.4 (C), 131.2 (C), 131.0 (CH), 130.9 (CH), 130.0 (C), 129.6 (2 CH), 129.5 (2 CH), 128.3 (CH), 128.2 (CH), 128.06 (C), 127.6 (CH), 127.6 (CH), 126.5 (CH), 126.3 (CH), 126.0 (CH), 123.7 (CH), 118.2 (q, J = 321 Hz, CF₃), 116.3 (CH), –0.4 (CH₃) ppm. MS (MALDI-TOF): m/z = 700 [M⁺]. 9,16-Diphenyl-13-(trimethylsilyl)dibenzo[de,uv]pentacen-12-yl Trifluoromethanesulfonate (19) Reaction of 9,11-diphenyl-10H-cyclopenta[e]pyren-10-one (11, 118 mg, 0.290 mmol), 3,6-bis(trimethylsilyl)-naphthalene-2,7-diyl bis(trifluoromethanesulfonate) (2, 150 mg, 0.264 mmol), and CsF (48 mg, 0.317 mmol) in MeCN–CH₂Cl₂ (2:1; 9 mL) afforded 19 (46 mg, 24%) as a yellow solid. ¹H NMR (500 MHZ, CDCl₃): δ = 8.52 (s, 1 H), 8.47 (s, 1 H), 8.06 (s, 1 H), 7.85 (m, 3 H), 7.82 (d, J = 7.7 Hz, 2 H), 7.73 (t, J = 8.4 Hz, 2 H), 7.65–7.57 (m, 10 H), 7.29 (td, J = 7.9, 1.2 Hz, 2 H), 0.44 (s, 9 H) ppm. ¹³C NMR (126 MHz, CDCl₃): δ = 152.4 (C), 142.1 (C), 142.0 (C), 139.1 (CH), 136.6 (C), 136.6 (C), 132.8 (2 CH), 132.76 (2 CH), 132.0 (C), 131.6 (C), 131.6 (C), 131.3 (C), 131.0 (C), 130.9 (C), 130.4 (C), 130.4 (C), 130.1 (C), 129.7 (CH), 129.6 (CH), 129.4 (CH), 129.3 (CH), 128.2 (CH), 128.1 (CH), 127.0 (CH), 127.0 (CH), 126.7 (CH), 126.6 (CH), 126.6 (CH), 126.4 (C), 126.3 (C), 126.1 (CH), 125.1 (CH), 125.1 (C), 118.2 (q, J = 322 Hz, CF₃), 116.29 (CH), 116.28 (CH), –0.43 (3 CH₃) ppm. MS (MALDI-TOF): m/z = 724 [M⁺].
• 17 The use of neat MeCN or CH₂Cl₂ resulted in lower conversions due to the poor solubility of either the diene (in MeCN) or the CsF (in CH₂Cl₂). On the other hand the use of TBAF as the fluoride source afforded lower yields of the expected triflates.
• 18 In parallel to the work described in this article, we also studied the generation of a naphtho[1,2,3,4-ghi]perylyne precursor by reaction of 8 with perylene: Schuler B, Collazos S, Gross L, Meyer G, Pérez D, Guitián E, Peña D. Angew. Chem. Int. Ed. 2014; 53: 9004
• 19 Pascal RA. Jr, McMillan WD, Van Engen D, Eason RG. J. Am. Chem. Soc. 1987; 109: 4660
• 20 Miao Q, Chi X, Xiao S, Zeis R, Lefernfeld M, Siegrist T, Steigerwald ML, Nuckolls C. J. Am. Chem. Soc. 2006; 128: 1340
• 21a Zhang Q, Divayana Y, Xiao J, Wang Z, Tiekink ER. T, Doung HM, Zhang H, Boey F, Sun XW, Wudl F. Chem. Eur. J. 2010; 16: 7422
• 21b Xiao J, Liu S, Liu Y, Ji L, Liu X, Zhang H, Sun X, Zhang Q. Chem. Asian J. 2012; 7: 561
• 21c Xiao J, Duong HM, Liu Y, Shi W, Ji L, Li G, Li S, Liu X.-W, Ma J, Wudl F, Zhang Q. Angew. Chem. Int. Ed. 2012; 51: 6094
• 22 We have already employed triflate 17 as an efficient precursor of tetraphenylanthracyne 20, in the synthesis of large benzofused acenes: Rodríguez-Lojo DR, Pérez D, Peña D, Guitián E. Chem. Commun. 2015; 51: 5418
• 23 Pentacene and larger acenes are paradigmatic organic semiconductors, although their poor solubility and low stability limit their application: Anthony JE. Angew. Chem. Int. Ed. 2008; 47: 452
• 24 Xiao J, Divayana Y, Zhang Q, Doung HM, Zhang H, Boey F, Sun XW, Wudl F. J. Mat. Chem. 2010; 20: 8617