Palladium-Catalyzed Decarboxylation of Benzyl Fluorobenzoates

Published as part of the Cluster CO Activation

Abstract

The decarboxylation of benzyl fluorobenzoates has been developed by using the palladium catalyst prepared in situ from Pd(η³-allyl)Cp and bulky monophosphine ligand XPhos. The catalytic reaction afforded a range of fluorinated diarylmethanes in good yields with broad functional-group compatibility. The substrates were readily synthesized by condensation of the corresponding benzoic acid with benzyl alcohol. Therefore, the transformation is formally regarded as a cross-coupling reaction between fluorine-containing benzoic acids and benzyl alcohols.

Key words

decarboxylation - benzylation - palladium catalyst - diarylmethane - fluoroarene - C–O activation - benzyl palladium intermediate

• References and Notes

• 1a Cross-Coupling Reactions . In Top. Curr. Chem., 2nd ed. Vol. 219. Miyaura N. Springer; Berlin: 2002
• 1b Metal-Catalyzed Cross-Coupling Reactions. de Meijere A. Diederich F. Wiley-VCH; Weinheim: 2004
• 1c Palladium Reagents and Catalysts: New Perspectives for the 21st Century. Tsuji J. John Wiley and Sons; London: 2004

For pioneering exapmles on decarboxylation of transition-metal carboxylate, see:
• 2a Shepard AF. Winslow NR. Johnson JR. J. Am. Chem. Soc. 1930; 52: 2083
• 2b Connett JE. Davies AG. Deacon GB. Green JH. S. Chem. Ind. (London) 1965; 12: 512
• 2c Nilsson M. Kulonen E. Sunner S. Frank V. Brunvoll J. Bunnenberg E. Djerassi C. Records R. Acta Chem. Scand. 1966; 20: 423
• 2d Nilsson M. Tetrahedron Lett. 1966; 7: 679
• 2e Schmeißer M. Weidenbruch M. Chem. Ber. 1967; 100: 2306
• 2f Sartori P. Weidenbruch M. Chem. Ber. 1967; 100: 3016
• 2g Sartori P. Golloch A. Chem. Ber. 1969; 102: 1765
• 2h Cairncross A. Roland JR. Henderson RM. Sheppard WA. J. Am. Chem. Soc. 1970; 92: 3187
• 2i Cohen T. Schambach RA. J. Am. Chem. Soc. 1970; 92: 3189

For reviews on decarboxylative couplings, see:
• 3a Tunge JA. Burger EC. Eur. J. Org. Chem. 2005; 1715
• 3b Gooßen LJ. Gooßen K. Rodríguez N. Blanchot M. Linder C. Zimmermann B. Pure Appl. Chem. 2008; 80: 1725
• 3c Gooßen LJ. Collet F. Gooßen K. Isr. J. Chem. 2010; 50: 617
• 3d Miura M. Satoh T. Synthesis 2010; 3395
• 3e Weaver JD. Recio III A. Grenning AJ. Tunge JA. Chem. Rev. 2011; 111: 1846
• 3f Rodriguez N. Gooßen LJ. Chem. Soc. Rev. 2011; 40: 5030
• 3g Shang R. Liu L. Sci. China: Chem. 2011; 54: 1670
• 3h Larrosa I. Cornella J. Synthesis 2012; 44: 653
• 3i Dzik WI. Lange PP. Gooßen LJ. Chem. Sci. 2012; 3: 2671
• 3j Ambler BR. Yang MH. Altman RA. Synlett 2016; 27: 2747
• 4a Wai JS. Egbertson MS. Payne LS. Fisher TE. Embrey MW. Tran LO. Melamed JY. Langford HM. Guare JP. Zhuang L. Grey VE. Vacca JP. Holloway MK. Naylor-Olsen AM. Hazuda DJ. Felock PJ. Wolfe AL. Stillmock KA. Schleif WA. Gabryelski LJ. Young SD. J. Med. Chem. 2000; 43: 4923
• 4b Long YQ. Jiang XH. Dayam R. Sanchez T. Shoemaker R. Sei S. Neamati N. J. Med. Chem. 2004; 47: 2561
• 4c Forsch RA. Queener SF. Rosowsky A. Bioorg. Med. Chem. Lett. 2004; 14: 1811
• 4d Xie W.-D. Li X. Weng C.-W. Liu S.-S. Row KH. Chem. Pharm. Bull. 2011; 59: 511
• 5a Kuwano R. Yokogi M. Org. Lett. 2005; 7: 945
• 5b Kuwano R. Yokogi M. Chem. Commun. 2005; 5899
• 5c Kuwano R. Yu J.-Y. Heterocycles 2007; 74: 233
• 5d Yu JY. Kuwano R. Org. Lett. 2008; 10: 973
• 5e Ohsumi M. Kuwano R. Chem. Lett. 2008; 37: 796
• 6a Lindsey CC. O’Boyle BM. Mercede SJ. Pettus TR. R. Tetrahedron Lett. 2004; 45: 867
• 6b McLaughlin M. Org. Lett. 2005; 7: 4875
• 6c Molander GA. Elia MD. J. Org. Chem. 2006; 71: 9198
• 6d Nakao Y. Ebata S. Chen J. Imanaka H. Hiyama T. Chem. Lett. 2007; 36: 606
• 6e Taylor BL. Harris MR. Jarvo ER. Angew. Chem. Int. Ed. 2012; 51: 7790
• 6f Harris MR. Hanna LE. Greene MA. Moore CE. Jarvo ER. J. Am. Chem. Soc. 2013; 135: 3303
• 6g Zhou Q. Srinivas HD. Dasgupta S. Watson MP. J. Am. Chem. Soc. 2013; 135: 3307

For reactions using electron-deficient arenes directly instead of aryl metal compounds, see:
• 7a Tabuchi S. Hirano K. Satoh T. Miura M. J. Org. Chem. 2014; 79: 5401
• 7b Yang G. Jiang X. Liu Y. Li N. Yin G. Yu C. Asian J. Org. Chem. 2016; 5: 882
• 8a Trost BM. Czabaniuk LC. Angew. Chem. Int. Ed. 2014; 53: 2826
• 8b Le Bras J. Muzart J. Eur. J. Org. Chem. 2016; 2565
• 9a Kuwano R. Kusano H. Org. Lett. 2008; 10: 1979
• 9b Torregrosa RR. Ariyarathna Y. Chattopadhyay K. Tunge JA. J. Am. Chem. Soc. 2010; 132: 9280
• 9c Fields WH. Chruma JJ. Org. Lett. 2010; 12: 316
• 9d Recio III A. Heinzman JD. Tunge JA. Chem. Commun. 2012; 48: 142
• 9e Mendis SN. Tunge JA. Org. Lett. 2015; 17: 5164
• 9f Mendis SN. Tunge JA. Chem. Commun. 2016; 52: 7695
• 9g Yang MH. Hunt JR. Sharifi N. Altman RA. Angew. Chem. Int. Ed. 2016; 55: 9080

For decarboxylative carbon–carbon bond formation of ortho-difluorinated benzoate through transition-metal catalysis, see:
• 10a Myers AG. Tanaka D. Mannion MR. J. Am. Chem. Soc. 2002; 124: 11250
• 10b Becht JM. Catala C. Drian CL. Wagner A. Org. Lett. 2007; 9: 1781
• 10c Becht JM. Le Drian C. Org. Lett. 2008; 10: 3161
• 10d Sun ZM. Zhao P. Angew. Chem. Int. Ed. 2009; 48: 6726
• 10e Shang R. Fu Y. Wang Y. Xu Q. Yu HZ. Liu L. Angew. Chem. Int. Ed. 2009; 48: 9350
• 10f Cornella J. Sanchez C. Banawa D. Larrosa I. Chem. Commun. 2009; 7176
• 10g Shang R. Xu Q. Jiang YY. Wang Y. Liu L. Org. Lett. 2010; 12: 1000
• 10h Xie K. Yang Z. Zhou X. Li X. Wang S. Tan Z. An X. Guo CC. Org. Lett. 2010; 12: 1564
• 10i Pfister KF. Grünberg MF. Gooßen LJ. Adv. Synth. Catal. 2014; 356: 3302
• 11a Kuwano R. Kondo Y. Matsuyama Y. J. Am. Chem. Soc. 2003; 125: 12104
• 11b Kuwano R. Kondo Y. Org. Lett. 2004; 6: 3545
• 11c Kuwano R. Kondo Y. Shirahama T. Org. Lett. 2005; 7: 2973
• 11d Yokogi M. Kuwano R. Tetrahedron Lett. 2007; 48: 6109
• 11e Ueno S. Komiya S. Tanaka T. Kuwano R. Org. Lett. 2012; 14: 338
• 12 For a review on biaryl monophosphine ligand, see: Surry DS. Buchwald SL. Angew. Chem. Int. Ed. 2008; 47: 6338
• 13a Cohen T. Berninger RW. Wood JT. J. Org. Chem. 1978; 43: 837
• 13b Gooßen LJ. Deng G. Levy LM. Science 2006; 313: 662
• 13c Gooßen LJ. Thiel WR. Rodríguez N. Linder C. Melzer B. Adv. Synth. Catal. 2007; 349: 2241
• 14 General Procedure; Palladium-Catalyzed Decarboxylation In a nitrogen-filled glove box, Pd(η³-allyl)Cp (1.1 mg, 5.0 μmol), XPhos (5.7 mg, 12 μmol), and toluene (0.5 mL) were placed in a vial containing a magnetic stirring bar. After 5 min stirring at r.t., benzyl benzoate 1 (0.5 mmol) was added. Then, the vial was sealed with a cap equipped with a PTFE-coated silicone rubber septum and removed from the glove box. The mixture was stirred at 140 °C until starting material consumed monitored by GC analysis. The resulting mixture was evaporated under reduced pressure. The crude material was purified by flash column chromatography on silica gel eluting with EtOAc/hexane to give the desired diarylmethane 2. Characterization data for selected product 2a (for all data, see Supporting Information) is described as follows.
• 15 1-Benzyl-2,6-difluorobenzene (2a) Yield 80%. ¹H NMR (400 MHz, CDCl₃, TMS): δ = 4.02 (s, 2 H), 6.87 (t, J = 7.6 Hz, 2 H), 7.10–7.22 (m, 2 H), 7.23–7.33 (m, 4 H). ¹³C {¹H} NMR (100 MHz, CDCl₃): δ = 28.1 (t, J = 3 Hz), 111.2 (dd, J = 7, 19 Hz), 116.8 (t, J = 20 Hz), 126.3, 127.8 (t, J = 10 Hz), 128.4, 128.5, 139.2, 161.4 (dd, J = 9, 247 Hz). IR (neat): 3064, 3031, 2940, 1593, 1470, 1265, 1009 cm^–1. Anal. Calcd for C₁₃H₁₀F₂: C, 4.94; H, 76.46. Found: C, 4.92; H, 76.55.