Partial Bromination and Fluoroalkylation of 5,10,15-Tris(pentafluorophenyl)corrole

Abstract

Partial bromination of the free base of 5,10,15-tris(pentafluorophenyl)corrole was carried out, and various mono-, di-, tri- or tetrabrominated corroles could be selectively produced by controlling the amounts of NBS used. Their consequent Suzuki cross-coupling reactions with arylboronic acids led to various β-substituted corroles in good yields. Fluoroalkylation of the corrole was also studied preliminarily; monofluoroalkylated corrole and five- and six-membered fluorinated ring-fused corroles were synthesized.

Key words

5,10,15-tris(pentafluorophenyl)corrole - partial bromination - Suzuki cross-coupling - fluoroalkylation

References and Notes

• 1 The Porphyrin Handbook   Vols. 1-20:  Kadish KM. Smith KM. Guilard R. Academic Press; San Diego: 2000-2003. 
• 2a Paolesse R. In The Porphyrin Handbook   Vol. 2:  Kadish KM. Smith KM. Guilard R. Academic Press; San Diego: 2000.  Chap. 11. p.201-232  
• 2b Erben C. Will S. Kadish KM. In The Porphyrin Handbook   Vol. 2:  Kadish KM. Smith KM. Guilard R. Academic Press; San Diego: 2000.  Chap. 12. p.233-300  
• 2c Paolesse R. Synlett  2008,  2215 
• 2d Gryko DT. J. Porphyrins Phthalocyanines  2008,  12:  906 
• 3a Gross Z. Galili N. Saltsman I. Angew. Chem. Int. Ed.  1999,  38:  1427 
• 3b Gross Z. Galili N. Simkhovich L. Saltsman I. Botoshsnsky M. Blaser D. Boese R. Goldberg I. Org. Lett.  1999,  1:  599 
• 3c Paolesse R. Jaquinod L. Nurco DJ. Mini S. Sagone F. Boschi T. Smith KM. Chem. Commun.  1999,  1307 
• 4 Hiroto S. Hisaki I. Shinokubo H. Osuka A. Angew. Chem. Int. Ed.  2005,  44:  6763 
• 5a Saltsman I. Mahammed A. Goldberg I. Tkachenko E. Botoshansky M. Gross Z. J. Am. Chem. Soc.  2002,  124:  7411 
• 5b Paolesse R. Nardis S. Venanzi M. Mastroianni M. Fronczek FR. Vicente MGH. Chem. Eur. J.  2003,  9:  1192 
• 5c Paolesse R. Nardis S. Sagone F. Khoury R. J. Org. Chem.  2001,  66:  550 
• 5d Wasbotten IH. Wondimagegn T. Ghosh A. J. Am. Chem. Soc.  2002,  124:  8104 
• 5e Golubkov G. Bendix J. Gray HB. Mahammed A. Goldberg I. Di Bilio AJ. Gross Z. Angew. Chem. Int. Ed.  2001,  40:  2132 
• 5f Saltsman I. Goldberg I. Gross Z. Tetrahedron Lett.  2003,  44:  5669 
• 6 Nardis S. Mandoj F. Paolesse R. Fronczek FR. Smith KM. Prodi L. Montalti M. Battistini G. Eur. J. Inorg. Chem.  2007,  2345 
• 7a Mandoj F. Nardis S. Pomarico G. Paolesse R. J. Porphyrins Phthalocyanines  2008,  12:  19 
• 7b Ngo TH. Van Rossom W. Dehaen W. Maes W. Org. Biomol. Chem.  2009,  7:  439 
• 7c Liu HY. Chen L. Yam F. Zhan HY. Ying X. Wang XL. Jiang HF. Chang CK. Chin. Chem. Lett.  2008,  19:  1000 
• 8a Horn S. Dahms K. Senge MO. J. Porphyrins Phthalocyanines  2008,  12:  1053 
• 8b Shen D.-M. Liu C. Chen X.-G. Chen Q.-Y. J. Org. Chem.  2009,  74:  206 ; and the references cited therein
• 9a Liu C. Shen D.-M. Zeng Z. Guo C.-C. Chen Q.-Y. J. Org. Chem.  2006,  71:  9772 
• 9b Zeng Z. Liu C. Jin L.-M. Guo C.-C. Chen Q.-Y. Eur. J. Org. Chem.  2005,  306 
• 9c Zeng Z. Jin L.-M. Guo C.-C. Chen Q.-Y. Acta Chim. Sin.  2004,  62:  288 
• 9d Jin L.-M. Yin J.-J. Chen L. Xiao J.-C. Guo C.-C. Chen Q.-Y. Eur. J. Org. Chem.  2006,  3405 
• 9e Jin L.-M. Chen L. Guo C.-C. Chen Q.-Y. J. Porphyrins Phthalocyanines  2005,  9:  109 
• 9f Jin L.-M. Chen L. Yin J.-J. Guo C.-C. Chen Q.-Y.
  J. Fluorine Chem.  2005,  126:  1321 
• 9g Jin L.-M. Zeng Z. Guo C.-C. Chen Q.-Y. J. Org. Chem.  2003,  68:  3912 
• 9h Chen L. Jin L.-M. Xiao J.-C. Guo C.-C. Chen Q.-Y. Synlett  2007,  2096 
• 9i Chen L. Jin L.-M. Guo C.-C. Chen Q.-Y. Synlett  2005,  963 
• 10 Gross Z. Mahammed A. J. Porphyrins Phthalocyanines  2002,  6:  553 
• 12 Scrivanti A. Beghetto V. Matteoli U. Antonaroli S. Marini A. Mandoj F. Paolesse R. Crociani B. Tetrahedron Lett.  2004,  45:  5861 
• 13 Thomas KE. Wasbotten IH. Ghosh A. Inorg. Chem.  2008,  47:  10469 
• 14 Jacques L. Arnaud B. Eur. J. Org. Chem.  2008,  417 

11

General Procedure for the Synthesis of Brominated Corroles: A solution of NBS (1.1 equiv was used for the synthesis of monobrominated corroles 2, 2.1 equiv for dibrominated corrole 3, 3.1 equiv for tribrominated corrole 4, and 4.4 equiv for tetrabrominated corrole 5) in MeCN (10 mL) was added dropwise to corrole 1 (50 mg, 1.0 equiv) dissolved in CH₂Cl₂ (10 mL) for 8 h at r.t. After the addition was completed, the mixture was stirred for further 30 min. Then, the mixture was subsequently washed with H₂O, sat. NaHCO₃ and brine. The organic layer was dried over anhyd Na₂SO₄, filtered, and concentrated under reduced pressure to yield the crude product, which was purified by flash column chromatography. Corrole 3: ^¹H NMR (300 MHz, CDCl₃): δ = 9.37 (d, J = 4.2 Hz, 1 H), 8.89 (d, J = 4.6 Hz, 1 H), 8.72 (d, J = 4.9 Hz, 1 H), 8.66 (d, J = 4.9 Hz, 1 H), 8.49 (overlapping d, 2 H). ^¹9F NMR (CDCl₃): δ = -137.66 (dd, ^¹ J = 24.2 Hz, ^² J = 8.1 Hz, 2 F),
-138.16 (dd, ^¹ J = 23.0 Hz, ^² J = 6.9 Hz, 2 F), -139.00 (t, J = 19.6 Hz, 2 F), -151.69 (t, J = 20.7 Hz, 2 F), -152.25 (t, J = 20.7 Hz, 1 F), -161.32 (td, ^¹ J = 23.0 Hz, ^² J = 6.9 Hz, 2 F),
-162.12 (t, J = 18.4 Hz, 4 F). MS (MALDI): m/z = 952.0 [M⁺]. UV-Vis (CH₂Cl₂): λ _max (rel. int.) = 423 (8), 562 (1.17), 637 (1) nm. HRMS (MALDI): m/z [M⁺] calcd for C₃₇H₉Br₂F₁₅N₄ ⁺: 951.8949; found: 951.8971.
Corrole 4: ^¹H NMR (300 MHz, CDCl₃): δ = 9.31 (s, 1 H), 8.82 (d, J = 4.5 Hz, 1 H), 8.69 (d, J = 4.5 Hz, 1 H), 8.62 (d, J = 4.5 Hz, 1 H), 8.52 (d, J = 4.5 Hz, 1 H). ^¹9F NMR (CDCl₃): δ = -137.88 (dd, ^¹ J = 25.0 Hz, ^² J = 7.3 Hz, 2 F), -138.20 (br s, 2 F), -139.01 (br s, 2 F), -151.40 (br s, 1 F), -151.64 (t,
J = 22.8 Hz, 1 F), -152.21 (br s, 1 F), -161.28 (dt, ^¹ J = 28.2 Hz, ^² J = 6.2 Hz, 4 F), -161.91 (br s, 2 F), -162.31 (br s, 2 F). MS (MALDI): m/z = 1029.8 [M⁺]. UV-Vis (CH₂Cl₂):
λ_max (rel. int.) = 424 (6.77), 570 (1.25), 641 (1) nm. HRMS (MALDI): m/z [M⁺] calcd for C₃₇H₈Br₃F₁₅N₄ ⁺: 1029.8054; found: 1029.8086. Crystal Data: C₃₈H₈Br₃F₁₅N₄, M = 1033.20, monoclinic, space group C2/c, a = 36.433 (16), b = 12.829 (6), c = 15.844 (7) Å, α = 90˚, β = 109.728 (6)˚, γ = 90˚, V = 6970 (6) Å^³, T = 293 (2) K, Z = 8, D _c = 1.969 g/
cm^-³, 10703 reflections measured, 6027 unique which were used in all calculations. R(int) = 0.1667. R ₁ = 0.2514. The final wR(F ^²) was 0.0895 (all data). CCDC No: 730338.
Corrole 5: ^¹H NMR (300 MHz, CDCl₃): δ = 8.64 (d, J = 4.8 Hz, 2 H), 8.45 (d, J = 4.8 Hz, 2 H). ^¹9F NMR (CDCl₃): δ =
-137.60 (dd, ^¹ J = 24.2 Hz, ^² J = 8.1 Hz, 2 F), -138.48 (dd, ^¹ J = 23.0 Hz, ^² J = 6.9 Hz, 4 F), -151.52 (d, 3 F), -161.17 (td, ^¹ J = 24.2 Hz, ^² J = 8.1 Hz, 2 F), -161.94 (td, ^¹ J = 23.0, ^² J = 6.9 Hz, 4 F). MS (MALDI): m/z = 1029.8 [M⁺]. UV-Vis (CH₂Cl₂): λ_max (rel. int.) = 424 (6.78), 571 (1.25), 639 (1) nm. HRMS (MALDI): m/z [M⁺] calcd for C₃₇H₇Br₄F₁₅N₄ ⁺: 1107.7159; found: 1107.7163.

15

General Procedure for Fluoroalkylation of Corrole 1: Corrole 1 (50 mg, 0.06 mmol) was dissolved in DMSO
(5 mL), then Na₂S₂O₄ (54.6 mg, 0.3 mmol) was added. To the mixture a DMSO (5 mL) solution of IC₄F₈Cl (2.0 equiv) was added dropwise during a period of time (ca. 3-4 h) under nitrogen at r.t. The resulting mixture was stirred for further 2 h. The progress of the reaction was monitored by TLC. After the reaction was finished, the reaction mixture was diluted with CH₂Cl₂ (20 mL), and washed with H₂O (3 ×). The organic layer was dried over anhyd Na₂SO₄, and concentrated under reduced pressure to dryness. The crude product was purified by flash column chromatography (silica gel, PE-CH₂Cl₂ = 5:1 as eluent) to provide the desired products. It should be noted that corrole 9a and 9b decomposed slowly during the column chromatography.
Corrole 9a: ^¹H NMR (300 MHz, CDCl₃): δ = 9.06 (s, 1 H), 8.79 (2 × d, 2 H), 8.70 (d, J = 4.6 Hz, 2 H), 8.57 (d, J = 5.1 Hz, 2 H), 8.51 (d, J = 4.6 Hz, 4 H), 8.48 (d, J = 4.1 Hz, 6 H). ^¹9F NMR (CDCl₃): δ = -68.45 (s, 2 F), -102.46 (s, 2 F), -119.82 (s, 2 F), -120.50 (s, 2 F), -137.8 to -138.8 (m, 6 F), -152.1 to -153.0 (m, 3 F), -161.6 to -163.8 (m, 6 F). MS (MALDI): m/z = 1120.2 [M⁺]. UV-Vis (CH₂Cl₂): λ_max (rel. int.) = 420 (13.5), 561 (2.2), 602 (1.4), 637 (1) nm. HRMS (MALDI): m/z [M + H⁺] calcd for C₄₁H₁₁F₂₃N₄Cl⁺: 1031.0299; found: 1031.0259.