Chroman-4-ones via Microwave-Promoted Domino Claisen Rearrangement–Oxa-Michael Addition: Synthesis of Tabchromones A and B

Abstract

Allyl phenyl ethers with a pendant enone substituent undergo, upon microwave irradiation, a domino sequence of Claisen rearrangement and 6-endo-trig-cyclization to furnish functionalized chroman-4-ones. The natural products tabchromones A and B were synthesized via this method.

Key words

cyclization - Michael addition - rearrangement - tandem reaction - Wacker reaction

• References and Notes

• 1 Breinbauer R, Vetter IR, Waldmann H. Angew. Chem. Int. Ed. 2002; 41: 2878
• 2 Horton DA, Bourne GT, Smythe ML. Chem. Rev. 2003; 103: 893
• 3 Saengchantara ST, Wallace TW. Nat. Prod. Rep. 1986; 3: 465
• 4 Sharma SK, Kumar S, Chand K, Kathuria A, Gupta A, Jain R. Curr. Med. Chem. 2011; 18: 3825
• 5 Khadem S, Marles RJ. Molecules 2011; 17: 191
• 6 Gaspar A, Matos MJ, Garrido J, Uriarte E, Borges F. Chem. Rev. 2014; 114: 4960
• 7 Mou DR, Zhao W, Zhang T, Wan L, Yang GY, Chen YK, Hu QF, Miao MM. Heterocycles 2012; 85: 2485
• 8 Ren D.-M, Guo H.-F, Yu W.-T, Wang S.-Q, Ji M, Lou H.-X. Phytochemistry 2008; 69: 1425
• 9 Cairns H, Cox D, Gould KJ, Ingall AH, Suschitzky JL. J. Med. Chem. 1985; 28: 1832
• 10 Joule JA, Mills K. Heterocyclic Chemistry . Blackwell; Oxford: 2000. 4th ed
• 11 Santamaria J, Valdés C In Modern Heterocyclic Chemistry . Vol. 3. Alvarez-Builla J, Vaquero JJ, Barluenga J. Wiley-VCH; Weinheim: 2011: 1631-1682
• 12 Renault J, Qian Z, Uriac P, Gouault N. Tetrahedron Lett. 2011; 52: 2476
• 13 Prasad KR, Nagaraju C. Org. Lett. 2013; 15: 2778
• 14 Wang X, Cheng G, Cui X. Chem. Commun. 2014; 50: 652
• 15 Tietze LF. Chem. Rev. 1996; 96: 115
• 16 Majumdar KC, Alam S, Chattopadhyay B. Tetrahedron 2008; 64: 597
• 17 Majumdar KC, Nandi RK. Tetrahedron 2013; 69: 6921
• 18 Ghosh AK, Cheng X, Zhou B. Org. Lett. 2012; 14: 5046
• 19 Nawghare BR, Sakate SS, Lokhande PD. J. Heterocycl. Chem. 2014; 51: 291
• 20 Patonay T, Varma RS, Vass A, Lévai A, Dudás J. Tetrahedron Lett. 2001; 42: 1403
• 21 Tarbell DS. Org. React. (N. Y.) 1944; 2: 1
• 22 Anwar HF, Hansen TV. Org. Lett. 2009; 11: 587
• 23 Yoshida M, Fujino Y, Saito K, Doi T. Tetrahedron 2011; 67: 9993
• 24 Jiménez-González L, Álvarez-Corral M, Munoz-Dorado M, Rodríguez-García I. Chem. Commun. 2005; 2689
• 25 Kappe CO. Angew. Chem. Int. Ed. 2004; 43: 6250
• 26 Kappe CO. Chimia 2006; 60: 308
• 27 Kappe CO. Chem. Soc. Rev. 2008; 37: 1127
• 28 Microwaves in Organic Synthesis . de la Hoz A, Loupy A. Wiley-VCH; Weinheim: 2012
• 29 Giguere RJ, Bray TL, Duncan SM, Majetich G. Tetrahedron Lett. 1986; 27: 4945
• 30 Martín Castro AM. Chem. Rev. 2004; 104: 2939
• 31 Schlüter J, Blazejak M, Hintermann L. ChemCatChem 2013; 5: 3309
• 32 Chen P.-K, Rosana MR, Dudley GB, Stiegman AE. J. Org. Chem. 2014; 79: 7425
• 33 McIntosh CE, Martínez I, Ovaska TV. Synlett 2004; 2579
• 34 Kremsner JM, Kappe CO. J. Org. Chem. 2006; 71: 4651
• 35 Baxendale IR, Lee A.-L, Ley SV. J. Chem. Soc., Perkin Trans. 1 2002; 1850
• 36 Razzaq T, Kremsner JM, Kappe CO. J. Org. Chem. 2008; 73: 6321
• 37 Daskiewicz J.-B, Bayet C, Barron D. Tetrahedron Lett. 2001; 42: 7241
• 38 Schmidt B, Riemer M, Karras M. J. Org. Chem. 2013; 78: 8680
• 39 Schmidt B, Riemer M. J. Org. Chem. 2014; 79: 4104
• 40 Ley SV, Norman J, Griffith WP, Marsden SP. Synthesis 1994; 639
• 41 CCDC 1007822 contains supplementary crystallographic data for this compound. These data can be obtained free of charge from the Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
• 42 Further crystallographic details, including a graphic depicting the molecular packing and intermolecular hydrogen bonds, can be found in the supporting information.
• 43 Synthesis of Tabchromone B; MOM-Protected Precursor 9: Allyl ether 8 (182 mg, 0.66 mmol) was dissolved in N,N-diethyl aniline or N,N-dimethyl aniline (4 mL) in a vessel suited for microwave irradiation. The vessel was closed, placed in a microwave reactor, and irradiated at 250 °C for 1 h. The mixture was then cooled to ambient temperature and diluted with EtOAc (40 mL). This solution was extracted three times with aqueous HCl (1 M, 10 mL for each extraction) to remove the solvent used for the microwave reaction, dried with MgSO₄, filtered and evaporated. The residue was purified by column chroma-tography on silica, using hexane–MTBE mixtures of increasing polarity as eluents, to furnish 9 (147 mg, 0.53 mmol, 81%). ¹H NMR (300 MHz, CDCl₃): δ = 7.37 (d, J = 3.1 Hz, 1 H), 7.05 (d, J = 3.1 Hz, 1 H), 5.93 (ddt, J = 17.2, 10.2, 6.6 Hz, 1 H), 5.02–5.16 (m, 4 H), 3.46 (s, 3 H), 3.34 (d, J = 6.7 Hz, 2 H), 2.68 (s, 2 H), 1.43 (s, 6 H). ¹³C NMR (75 MHz, CDCl₃): δ = 192.7, 153.3, 150.7, 136.0, 131.3, 126.5, 120.3, 116.3, 110.0, 95.2, 79.0, 56.2, 48.9, 34.1, 26.8. IR (ATR): 2978 (br w), 1689 (s), 1466 (s), 1153 (s), 1022 (s) cm^–1. HRMS (EI): m/z [M⁺] calcd for C₁₆H₂₀O₄ ⁺: 276.1362; found: 276.1351. LRMS (EI): m/z (%) = 276 (100) [M⁺], 261 (75) [M⁺ – Me], 231 (35) [M⁺ –EtO]. Deprotection of 9: A solution of 9 (79 mg, 0.29 mmol) and p-TSA·H₂O (190 mg) in MeOH (10 mL) was stirred at ambient temperature for 12 h. The mixture was diluted with EtOAc (50 mL), washed three times with brine (10 mL for each cycle) and H₂O (10 mL). The organic layer was dried with MgSO₄, filtered and concentrated under reduced pressure. The residue crystallized to furnish tabchromone B (60 mg, 0.26 mmol, 90%) without further purification; colorless crystals; mp 82–85 °C. ¹H NMR (300 MHz, CDCl₃): δ = 7.25 (d, J = 3.0 Hz, 1 H, H-5), 6.97 (dd, J = 3.1, 0.5 Hz, 1 H, H-7), 5.95 (ddt, J = 17.3, 10.3, 6.6 Hz, 1 H, H-12), 5.65 (s, 1 H, H-OH), 5.03–5.15 (m, 2 H, H-13), 3.35 (d, J = 6.7 Hz, 2 H, H-11), 2.72 (s, 2 H, H-3), 1.45 (s, 6 H, H-14). ¹³C NMR (75 MHz, CDCl₃): δ = 193.7 (C-4), 152.5 (C-9), 149.3 (C-6), 136.0 (C-12), 131.5 (C-8), 125.1 (C-7), 120.2 (C-10), 116.4 (C-13), 108.9 (C-5), 78.9 (C-2), 48.9 (C-3), 34.0 (C-11), 26.7 (2 × C, C-14). IR (ATR): 3356 (br m), 1669 (s), 1465 (s), 1331 (m), 922 (m) cm^–1. HRMS (EI): m/z [M⁺] calcd. for C₁₄H₁₆O₃ ⁺: 232.1099; found: 232.1091. LRMS (EI): m/z (%) = 217 (100) [M⁺ – Me], 177 (50) [M⁺ – C₄H₇], 148 (45) [M⁺ – C₅H₈O], 232 (40) [M⁺].