Synlett 2009(9): 1477-1479  
DOI: 10.1055/s-0029-1217177
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Regioselective Synthesis of 2-Arylthio-4-methoxybenzoates by Formal [3+3] Cyclocondensations of 3-Arylthio-1-trimethylsilyloxybuta-1,3-dienes with 3-Oxo-orthoesters

Muhammad Imrana, Inam Iqbala, Peter Langer*a,b
a Institut für Chemie, Universität Rostock, Albert Einstein Str. 3a, 18059 Rostock, Germany
Fax: +49(381)4986412; e-Mail: peter.langer@uni-rostock.de;
b Leibniz-Institut für Katalyse an der Universität Rostock e.V., Albert Einstein Str. 29a, 18059 Rostock, Germany
Further Information

Publication History

Received 11 December 2008
Publication Date:
13 May 2009 (online)

Abstract

A variety of 2-arylthio-4-methoxybenzoates are regio­selectively prepared by the first formal [3+3] cyclocondensations of 3-arylthio-1-trimethylsilyloxybuta-1,3-dienes with 3-oxo-ortho­esters.

    References and Notes

  • 1a Behar V. Danishefsky SJ. J. Am. Chem. Soc.  1993,  115:  7017 
  • 1b Toste FD. Still IWJ. J. Am. Chem. Soc.  1995,  117:  7261 
  • 1c Davidson BS. Molinski TF. Barrows LR. Ireland CM. J. Am. Chem. Soc.  1991,  113:  4709 
  • 1d Mori Y. Taneda S. Hayashi H. Sakushima A. Kamata K. Suzuki AK. Yoshino S. Sakata M. Sagai M. Seki K.-i. Biol. Pharm. Bull.  2002,  25:  145 
  • 1e Davis RA. Sandoval IT. Concepcion GP. Moreira da Rocha R. Ireland CM. Tetrahedron  2003,  59:  2855 
  • 1f Liu H. Fujiwara T. Nishikawa T. Mishima Y. Nagai H. Shida T. Tachibana K. Kobayashi H. Mangindaan REP. Namikoshi M. Tetrahedron  2005,  61:  8611 
  • 1g Kaplan ML. Reents WD. Tetrahedron Lett.  1982,  23:  373 
  • 1h Hosoya Y. Adachi H. Nakamura H. Nishimura Y. Naganawa H. Tetrahedron Lett.  1996,  37:  9227 
  • See, for example:
  • 2a Glass HB. Reid EE. J. Am. Chem. Soc.  1929,  51:  3428 
  • 2b Dougherty G. Hammond PD.
    J. Am. Chem. Soc.  1935,  57:  117 
  • 2c For the trifluoromethanesulfonic acid catalyzed sulfurization of cycloalkanes, see: Olah GA. Wang Q. Prakash GKS. J. Am. Chem. Soc.  1990,  112:  3697 
  • 3 Kemp DS. Carey RI. Dewan JC. Galakatos NG. Kerkman D. Leung S.-L. J. Org. Chem.  1989,  54:  1589 ; and references cited therein
  • 4 Chua M. Hoyer H. Z. Naturforsch., B: J. Chem. Sci.  1965,  20:  416 
  • 5a Baxter I. Ben-Haida A. Colquhoun HM. Hodge P. Kohnke FH. Williams DJ. Chem. Eur. J.  2000,  6:  4285 ; and references cited therein
  • 5b Campbell JR. J. Org. Chem.  1964,  29:  1830 
  • 6a Taniguchi N. J. Org. Chem.  2007,  72:  1241 
  • 6b Fernández-Rodríguez MA. Shen Q. Hartwig JF. J. Am. Chem. Soc.  2006,  128:  2180 
  • 6c Murata M. Buchwald SL. Tetrahedron  2004,  60:  7397 
  • 7a Gendre F. Yang M. Diaz P. Org. Lett.  2005,  7:  2719 
  • 7b Bates CG. Gujadhur RK. Venkataraman D. Org. Lett.  2002,  4:  2803 
  • 7c Rábai J. Synthesis  1989,  523 
  • 8a Hilt G. Lüers S. Synthesis  2003,  1784 
  • 8b Hilt G. Lüers S. Harms K. J. Org. Chem.  2004,  69:  624 
  • 9a Rashid MA. Reinke H. Langer P. Tetrahedron Lett.  2007,  48:  2321 
  • 9b Rashid MA. Rasool N. Adeel M. Reinke H. Fischer C. Langer P. Tetrahedron  2008,  64:  3782 
  • 10 For a review of [3+3] cyclizations, see: Feist H. Langer P. Synthesis  2007,  327 
  • 11 For a review of 1,3-bis(silyloxy)buta-1,3-dienes, see: Langer P. Synthesis  2002,  441 
  • 12a Chan T.-H. Brownbridge P. J. Am. Chem. Soc.  1980,  102:  3534 
  • 12b Brownbridge P. Chan T.-H. Brook MA. Kang GJ. Can. J. Chem.  1983,  61:  688 
  • 13a Chan TH. Prasad CVC. J. Org. Chem.  1986,  51:  3012 
  • 13b Chan TH. Prasad CVC. J. Org. Chem.  1987,  52:  110 
  • 14 Rashid MA. Rasool N. Iqbal I. Imran M. Langer P. Tetrahedron Lett.  2008,  49:  2466 
  • 15 Lubbe M. Gütlein J.-P. Reinke H. Langer P. Synlett  2008,  2671 
  • 16a Wilson BD. Synthesis  1992,  283 
  • 16b Heilbron I. Jones ERH. Julia M. J. Chem. Soc.  1949,  1434 
  • 16c Searles S. Sanchez RA. Soulen RL. Kundinger DG. J. Org. Chem.  1967,  32:  2655 
  • 16d Banville J. Brassard P. J. Chem. Soc., Perkin Trans. 1  1976,  1852 
  • 16e Barker D. Brimble MA. Do P. Turner P. Tetrahedron  2003,  59:  2441 
  • 17 Iqbal I. Imran M. Villinger A. Langer P. Synthesis  2009,  297 
18

General Experimental Procedure
To a CH2Cl2 soln (3 mL/mmol of 1) of 2 (1.5 mmol) and 1 (2.25 mmol) was added TiCl4 (2.25 mmol) at -78 ˚C. The solution was allowed to warm to 20 ˚C within 20 h. To the solution was added HCl (10%, 25 mL). The organic and the aqueous layer were separated and the latter was extracted with CH2Cl2 (3 × 20 mL). The combined organic layers were dried (Na2SO4), filtered, and the filtrate was concentrated in vacuo, and the residue was purified by chromatography (SiO2, EtOAc-n-heptane = 1:9).
4-Methoxy-6-methyl-2-(3-tolylsulfanyl)benzoic Acid Methyl Ester (3b)
Starting with 1a (2.25 mmol), 2b (1.5 mmol), and TiCl4 (2.25 mmol), 3b was isolated as a yellow oil (226 mg, 50%). ¹H NMR (250 MHz, CDCl3): δ = 2.25 (s, 3 H, CH3), 2.30 (s, 3 H, CH3), 3.69 (s, 3 H, OCH3), 3.87 (s, 3 H, OCH3), 6.57-7.39 (m, 6 H, Ar). ¹³C NMR (63 MHz, CDCl3): δ = 20.4 (CH3), 21.2 (CH3), 51.9 (OCH3), 55.2 (CH3O), 114.1, 114.5, (CHAr), 126.9, 128.3 (C), 129.4, 131.5, 132.1, 133.0 (CHAr), 138.3, 139.1, 140.1, 146.9, 168.8 (C). IR (KBr): ν = 2998 (w), 2947 (w), 2834 (w), 2735 (w), 2570 (w), 1724 (s), 1589 (s), 1564 (m), 15560 (m), 1471 (m), 1426 (m), 1380 (w), 1302 (m), 1264 (s), 1217 (s), 1187 (m), 1136 (s), 1090 (s), 1047 (s), 998 (m), 960 (m), 776 (s), 691 (s), 608 (m). MS (EI): m/z (%) = 302 (100) [M+], 272 (11), 271 (61), 270 (21), 269 (86), 256 (18), 255 (49),228 (17), 227 (13), 184 (15), 121 (3), 91 (4), 65 (5). HRMS (EI): m/z calcd for C17H18O2O3S [M+]: 302.09712; found: 302.097152.