Cycloaddition of Styrenes as Phenylacetylene Substitutes on 2H-Pyran-2-ones and the Consequent Metal-Free Dehydrogenation: Case Study of Boscalid Derivatives­

Dedicated to Professor Bojan Verček, University of Ljubljana, Slovenia, on the occasion of his 65th birthday

Abstract

A novel use of styrenes as synthetic equivalents of phenylacetylenes is presented. To show its applicability, the method was tested for the preparation of a set of derivatives of boscalid, a commercially important fungicide. The strategy incorporates the Diels–Alder reaction of 3-acylamino-2H-pyran-2-ones with styrenes, followed by an efficient dehydrogenation step. The latter can be achieved either by the use of chloranil as the oxidant (under microwave irradiation) or by the application of activated charcoal Darco KB acting as a dehydrogenation catalyst (conventional heating).

Key words

cycloaddition - dehydrogenation - biaryls - heterogeneous catalysis - boscalid derivatives - heterocycles

• References

• 1a Matheron ME, Porchas M. Plant Dis. 2004; 88: 665
• 1b Avenot HF, Michailides TJ. Crop Prot. 2010; 29: 643
• 2a Ehrenfreund J, Lamberth C, Tobler H, Walter H. Patent WO2004058723, 2004 ; Chem. Abstr. 2004, 141, 565219.
• 2b Rouhi AM. Chem. Eng. News 2004; 82 (36): 49
• 2c Gooßen LJ, Deng G, Levy LM. Science 2006; 313: 662
• 3 Glasnov TN, Kappe CO. Adv. Synth. Catal. 2010; 352: 3089
• 4 Felpin F.-X, Fouquet E, Zakri C. Adv. Synth. Catal. 2009; 351: 649
• 5 Spivey AC, Tseng C.-C, Hannah JP, Gripton CJ. G, de Fraine P, Parr NJ, Scicinski JJ. Chem. Commun. 2007; 2926
• 6 Caron L, Campeau L-C, Fagnou K. Org. Lett. 2008; 10: 4533
• 7 Wetzel A, Ehrhardt V, Heinrich MR. Angew. Chem. Int. Ed. 2008; 47: 9130
• 8a Avenot HF, Michailides TJ. Plant Dis. 2007; 91: 1345
• 8b Wharton P, Fairchild K, Belcher A, Wood E. Plant Dis. 2012; 96: 454
• 8c Fernández-Ortuño D, Chen F, Schnabel G. Plant Dis. 2012; 96: 1198
• 8d Gewehr M, Dietz J, Grote T, Blettner C, Grammenos W, Hünger U, Müller B, Schieweck F, Schwögler A, Lohmann JK, Rheinheimer J, Schäfer P, Strathmann S, Stierl R (BASF) WO2006087343, 2006 ; Chem. Abstr. 2006, 145, 849774.
• 8e Dunkel R, Rieck H, Elbe H.-L, Wachendorff-Neumann U, Kuck K.-H (Bayer Cropscience) WO2003070705, 2003 ; Chem. Abstr. 2003, 139, 678788.
• 8f Jörges W, Heinrich J.-D, Lantzsch R (Bayer Cropscience) WO2006024388, 2006 ; Chem. Abstr. 2006, 144, 190961.
• 8g Liu P, Yang G.-q, Lv L, Li Z.-n, Li B. Shenyang Huagong Daxue Xuebao 2012; 26: 311 ; Chem. Abstr. 2013, 151, 110142
• 9a Kranjc K, Štefane B, Polanc S, Kočevar M. J. Org. Chem. 2004; 69: 3190
• 9b Kranjc K, Kočevar M. New J. Chem. 2005; 29: 1027
• 9c Kranjc K, Kočevar M. Collect. Czech. Chem. Commun. 2006; 71: 667
• 9d Štefane B, Perdih A, Pevec A, Šolmajer T, Kočevar M. Eur. J. Org. Chem. 2010; 5870

The synthesis of 8a–c,l starts from appropriate compounds containing activated CH₂ groups (i.e., 1,3-diketones, β-keto esters, etc.), C₁-synthon (DMFDMA, trimethyl or triethyl orthoformate, etc.) and hippuric acid as described in:
• 10a Kepe V, Kočevar M, Polanc S, Verček B, Tišler M. Tetrahedron 1990; 46: 2081
• 10b Kepe V, Kočevar M, Polanc S. J. Heterocycl. Chem. 1996; 33: 1707
• 11a Kočevar M. Acta Chim. Slov. 1996; 43: 143 ; Chem. Abstr. 1996, 125, 576047
• 11b Požgan F, Krejan M, Polanc S, Kočevar M. Heterocycles 2006; 69: 123
• 11c Požgan F, Kranjc K, Kepe V, Polanc S, Kočevar M. ARKIVOV 2007; (viii): 97
• 12 Sigma-Aldrich on their home page (www.sigmaaldrich.com) offers 4-chlorophenylacetylene (1 g) for approximately € 160 and 4-chlorostyrene (10 g) for approximately € 40.
• 13a Shusherina NP. Russ. Chem. Rev. 1974; 43: 1771
• 13b Afarinkia K, Vinader V, Nelson TD, Posner GH. Tetrahedron 1992; 48: 9111
• 13c Woodard BT, Posner GH In Advances in Cycloaddition . Vol. 5. Harmata M. JAI Press; Greenwich: 1999: 47-83
• 13d Tolmachova NA, Gerus II, Vdovenko SI, Essers M, Fröhlich R, Haufe G. Eur. J. Org. Chem. 2006; 4704
• 13e Singh RP, Bartelson K, Wang Y, Su H, Lu X, Deng L. J. Am. Chem. Soc. 2008; 130: 2422
• 13f Kranjc K, Kočevar M. Synlett 2008; 2613
• 13g Wu W, He S, Zhou X, Lee C.-S. Eur. J. Org. Chem. 2010; 1124
• 13h Afarinkia K, Abdullahi MH, Scowen IJ. Org. Lett. 2010; 12: 5564
• 13i Juranovič A, Kranjc K, Perdih F, Polanc S, Kočevar M. Tetrahedron 2011; 67: 3490
• 13j Juranovič A, Kranjc K, Polanc S, Perdih F, Kočevar M. Monatsh. Chem. 2012; 143: 771
• 14a Hayashi M. Chem. Rec. 2008; 8: 252
• 14b Kawashita Y, Hayashi M. Molecules 2009; 14: 3073
• 14c Krivec M, Gazvoda M, Kranjc K, Polanc S, Kočevar M. J. Org. Chem. 2012; 77: 2857
• 15a Osakai T, Akagi N, Hotta H, Ding J, Sawada S. J. Electroanal. Chem. 2000; 490: 85
• 15b Ho T.-L, Fieser M, Fieser L, Danheiser R, Roush W. Chloranil . In Fieser and Fieser’s Reagents for Organic Synthesis . Wiley-VCH; New York: 2010. (doi: 10.1002/9780471264194.fos02353.pub2)
• 16a Strauss CR. Aust. J. Chem. 2009; 62: 3
• 16b Kranjc K, Kočevar M. Curr. Org. Chem. 2010; 14: 1050
• 16c Moseley JD, Kappe CO. Green Chem. 2011; 13: 794
• 16d Baig RB. N, Varma RS. Chem. Soc. Rev. 2012; 41: 1559
• 16e Kranjc K, Kočevar M. Curr. Org. Chem. 2013; 17: 448
• 16f Kranjc K, Kočevar M. Curr. Org. Chem. 2013; 17: 457

See, for example:
• 17a Corey EJ, Cheng X.-M. The Logic of Chemical Synthesis . Wiley; New York: 1995
• 17b Sauer J, Heldmann DK. Tetrahedron Lett. 1998; 39: 2549