Abstract
The site-selective cleavage of an Ar–X bond in polyhalogenated aromatics is an important tool in synthetic planning especially when more than one identical halogen atom is present. An alternative to the usual metal-catalyzed cleavage is represented by photochemistry although only a few examples have been reported. We then investigated the feasibility of the site-selective photodechlorination of some dichloroanisoles through a combined experimental and computational study. In the case of 2,4-dichloroanisole, selective detachment of the chlorine atom at the ortho position with respect to the OMe group was observed upon photohomolysis (in cyclohexane) or photoheterolysis (in MeOH) of the Ar–Cl bond. In the latter case, 5-chloro-2-methoxy-1,1′-biphenyl was exclusively formed upon reaction of the resulting phenyl cation with benzene. The substitution of an OH group for a OMe group was detrimental since a lower photoreactivity resulted with no improvement in the selectivity.
Similar content being viewed by others
References
H. Amii and K. Uneyama, C-F Bond Activation in Organic Synthesis, Chem. Rev., 2009, 109, 2119–2183; Modern Arylation Methods, ed. L. Ackermann, Wiley-VCH Verlag GmbH & Co, 2009, pp. 513-535
Handbook of Organopalladium Chemistry for Organic Synthesis, ed. E. Negishi, Wiley Interscience, New York, 2002, vol. 1
Top. Curr. Chem., in Cross-Coupling Reactions-A Practical Guide, ed. N. Miyaura, Springer, Heidelberg, 2002, vol. 219.
See for example: J. Blum, O. Berlin, D. Milstein, Y. Ben-David, B. C. Wassermann, S. Schutte and H. Schumann, Palladium-Catalyzed Cross-Methylation of Aryl Chlorides by Stabilized Dimethylaluminium and -Gallium Reagents, Synthesis, 2000, 571–575; S. M. Dirk, D. W. Price Jr., S. Chanteau, D. V. Kosynkin and J. M. Tour, N-Acyliminium ion chemistry and palladium catalysis: a useful combi- nation to obtain bicyclic heterocycles, Tetrahedron, 2001, 57, 5109-5121; X. Mei, A. T. August and C. Wolf, Regioselective Copper-Catalyzed Amination of Chlorobenzoic Acids: Synthesis and Solid-State Structures of N-Aryl Anthranilic Acid Derivatives, J. Org. Chem., 2006, 71, 142-149; T. Schaub, M. Backes and U. Radius, Catalytic C-C Bond Formation Accomplished by Selective C-F Activation of Perfluorinated Arenes, J. Am. Chem. Soc., 2006, 128, 15964-15965; T. Wang, B. J. Alfonso and J. A. Love, Platinum(II)-Catalyzed Cross-Coupling of Polyfluoroaryl Imines, Org. Lett., 2007, 9, 5629-5631; L. Ackermann and A. Althammer, Domino N-H/C-H bond activation: palla- dium-catalyzed synthesis of annulated heterocycles using dichloro(hetero)arenes, Angew. Chem., Int. Ed., 2007, 46, 1627-1629; I. N. Houpis, J.-P. V. Hoeck and U. Tilstam, Carboxylate-Directed Kumada Coupling of an Acetaldehyde Synthon with 2-Bromobenzoates Used towards the Synthesis of Isochromanes, Synlett, 2007, 2179-2184; Y. Yamamoto and K. Hattori, Synthesis of multiply functio- nalized benzenes via ruthenium-catalyzed cycloaddition of diiododiynes, Tetrahedron, 2008, 64, 847-855; J. Almond-Thynne, D. C. Blakemore, D. C. Pryde and A. C. Spivey, Site- selective Suzuki-Miyaura coupling of heteroaryl halides - understanding the trends for pharmaceutically important classes, Chem. Sci., 2017, 8, 40-62.
S. M. Senaweera, A. Singh and J. D. Weaver, Photocatalytic Hydrodefluorination: Facile Access to Partially Fluorinated Aromatics, J. Am. Chem. Soc., 2014, 136, 3002–3005.
M. Freccero, M. Fagnoni and A. Albini, Homolytic vs. Heterolytic Paths in the Photochemistry of Haloanilines, J. Am. Chem. Soc., 2003, 125, 13182–13190.
A. Albini and M. Fagnoni, Photochemically-generated inter- mediates in synthesis, John Wiley & Sons, Hoboken, 2013, pp. 260–301.
V. Dichiarante and M. Fagnoni, Aryl Cation Chemistry as an Emerging Versatile Tool for Metal-Free Arylations, Synlett, 2008, 787–800.
S. Lazzaroni, D. Ravelli, S. Protti, M. Fagnoni and A. Albini, Photochemical synthesis: Using light to build C-C bonds under mild conditions, C. R. Chim., 2017, 20, 261–271
V. Dichiarante, S. Protti and M. Fagnoni, Phenyl cation: a versatile intermediate, J. Photochem. Photobiol., A, 2017, 339, 103–113.
S. Protti, M. Fagnoni, M. Mella and A. Albini, Aryl Cations from Aromatic Halides. Photogeneration and Reactivity of 4-Hydroxy(methoxy)phenyl Cation, J. Org. Chem., 2004, 69, 3465–3473.
C. Raviola, F. Chiesa, S. Protti, A. Albini and M. Fagnoni, On the Route to the Photogeneration of Heteroaryl Cations. The Case of Halothiophenes, J. Org. Chem., 2016, 81, 6336–6342.
E. Fasani, M. Mella, D. Caccia, S. Tassi, M. Fagnoni and A. Albini, The photochemistry of lomefloxacin. An aromatic carbene as the key intermediate in photodecomposition, Chem. Commun., 1997, 1329–1330.
M. H. L. Stegeman, W. J. G. M. Peijnenburg and H. Verboom, A Quantitive Structure-Activity relationship for direct photohydrolysis of met-substituted halobenzene in water, Chemosphere, 1993, 26, 837–849.
M. Mansour, H. Parlar and F. Korte, Photodechlorierungsreaktionen an Dichloranisolen und Dichlortoluolen in Gegenwart von Protonendonatoren, Naturwissenschaften, 1979, 66, 579–580.
A. Aballay, E. Clot, O. Eisenstein, M.-T. Garland, F. Godoy, A. U. Klahn, J. H. Muñozc and B. Oelckersa, Selectivity in C-Cl bond activation of dichloroarenes by photogenerated Cp*Re(CO)2: combined experimental and DFT studies, New J. Chem., 2005, 29, 226–231.
V. Dichiarante, D. Dondi, S. Protti, M. Fagnoni and A. Albini, A meta effect in organic photochemistry? The case of SN1 reactions in methoxyphenyl derivatives, J. Am. Chem. Soc., 2007, 129, 5605–5611. Correction: 11662.
A. Kar, N. Mangu, H.-M. Kaise and M.-K. Tse, Gold-cata- lyzed direct oxidative coupling reactions of non-activated arenes, J. Organomet. Chem., 2009, 694, 524–537.
A. V. Marenich, C. J. Cramer and D. G. Truhlar, Universal solvation model based on solute electron density and on a continuum model of the solvent defined by the bulk dielec- tric constant and atomic surface tensions, J. Phys. Chem. B, 2009, 113, 6378–6396.
C. M. Previtali and T. W. Ebbesen, Laser flash photolysis of chlorobenzene in polar solvents, J. Photochem., 1985, 30, 259–267.
K.-L. Han and G. Z. He, Photochemistry of aryl halides: Photodissociation dynamics, J. Photochem. Photobiol., C, 2007, 8, 55–66.
C. Raviola, D. Ravelli, S. Protti, A. Albini and M. Fagnoni, Conditions and Edges for the Photochemical Generation of Short-Lived Aryl Cations: A Computational Approach, Synlett, 2015, 471–478.
B. J. Groombridge, S. M. Goldup and I. Larrosa, Selective and general exhaustive cross-coupling of di- chloroarenes with a deficit of nucleophiles mediated by a Pd-NHC complex, Chem. Commun., 2015, 51, 3832–3834
M. Platon, J. Roger, S. Royer and J.-C. Hierso, Palladium C-N bond formation catalysed by air-stable robust polydentate ferrocenylphosphines: a comparative study for the efficient and selective coupling of aniline derivatives to dichloroarene, Catal. Sci. Technol., 2014, 4, 2072–2080
T. Kitamura, K. Gondo and T. Katagiri, Synthesis of 1,2-Bis(trimethylsilyl)benzene Derivatives from 1,2-Dichlorobenzenes Using a Hybrid Metal Mg/ CuCl in the Presence of LiCl in 1,3-Dimethyl-2-imidazoli- dinone, J. Org. Chem., 2013, 78, 3421–3424
G. S. Reddy and W. Tam, Monoalkylation of dichloro- arenes with Grignard reagents catalyzed by a nickel complex, Organometallics, 1984, 3, 630–632
I. V. Kuchurov, A. A. Vasil’ev and S. G. Zlotin, The Suzuki-Miyaura cross-coupling of bromo- and chloro- arenes with arylboronic acids in supercritical carbon dioxide, Mendeleev Commun., 2010, 20, 140–142
J.-R. Wang and K. Manabe, High Ortho Preference in Ni-Catalyzed Cross-Coupling of Halophenols with Alkyl Grignard Reagents, Org. Lett., 2009, 11, 741–744
M. Kimura, H. Miyahara, N. Moritani and Y. Sawaki, Electroreductive dehalogenation of chlorinated aromatic ethers. Unexpected electrogenerated base-catalyzed reac- tions, J. Org. Chem., 1990, 55, 3897–3902
T. S. Khaibulova, I. A. Boyarskaya, E. Larionov and V. P. Boyarskiy, Cobalt-Catalyzed Methoxycarbonylation of Substituted Dichlorobenzenes as an Example of a Facile Radical Anion Nucleophilic Substitution in Chloroarenes, Molecules, 2014, 19, 5876–5897.
M. Yamaguchi, T. Akiyama, H. Sasou, H. Katsumata and K. Manabe, One-Pot Synthesis of Substituted Benzo[b] furans and Indoles from Dichlorophenols/Dichloroanilines Using a Palladium-Dihydroxyterphenylphosphine Catalyst, J. Org. Chem., 2016, 81, 5450–5463.
K. Kobayashi, M. Arisawa and M. Yamaguchi, GaCl3- Catalyzed Ortho-Ethynylation of Phenols, J. Am. Chem. Soc., 2002, 124, 8528–8529.
B. Li, J. Lan, D. Wu and J. You, Rhodium(III)-Catalyzed ortho-Heteroarylation of Phenols through Internal Oxidative C-H Activation: Rapid Screening of Single-Molecular White-Light-Emitting Materials, Angew. Chem., Int. Ed., 2015, 54, 14008–14012.
J. Hu, E. A. Adogla, Y. Ju, D. Fan and Q. Wang, Copper-cata- lyzed ortho-acylation of phenols with aryl aldehydes and its application in one-step preparation of xanthones, Chem. Commun., 2012, 48, 11256–11258.
Acknowledgments
We thank Dr Davide Ravelli and Dr Stefano Protti (University of Pavia) for fruitful discussion.
This work was funded by the CINECA Supercomputer Center, with the computer time granted by ISCRA projects (code: HP10CN4237 and HP10CBEIAU).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Raviola, C., Fagnoni, M. Search for a photoinduced (site-selective) cleavage of the Ar–Cl bond in dichloroanisoles. Photochem Photobiol Sci 17, 107–117 (2018). https://doi.org/10.1039/c7pp00372b
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1039/c7pp00372b