Synlett 2003(4): 0579-0581
DOI: 10.1055/s-2003-37519
LETTER
© Georg Thieme Verlag Stuttgart · New York

Stereospecific Synthesis of Chalcogenoenynes by Palladium-Catalyzed Cross-Coupling Reaction

Gilson Zeni*a, Cristina W. Nogueiraa, Jesus M. Penaa, Cristiane Pilissãoa, Paulo H. Menezesb, Antonio L. Bragaa, João B. T. Rochaa
a Departamento de Química - Laboratório de Bioquímica Toxicológica -, UFSM 97105-900, Santa Maria, RS, Brazil
e-Mail: gzeni@quimica.ufsm.br;
b Departamento de Química Fundamental, UFPE, Recife, PE, Brazil
Further Information

Publication History

Received 10 January 2003
Publication Date:
26 February 2003 (online)

Abstract

A new methodology for the synthesis of chalcogenoenynes is described. The palladium-catalyzed cross-coupling reaction of 1,2-bis(organanylchalcogeno)-alkenes and 1-alkynes gave the corresponding chalcogenoenynes in 71% to 88% yields. Preliminary pharmacologycal tests suggest that chalcogenoenynes may be useful drugs as anti-inflammatory and antinociceptive agents.

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Pd(II) Catalyzed Cross-Coupling Reaction of 1,2-Bis(organanylchalcogeno)-alkenes 1a with 2-Propyn-1-ol; General Procedure: To a solution of PdCl2 (20 mol%, 0.035 g), CuI (20 mol%, 0.038g) in MeOH (5 mL) at room temperature under argon atmosphere, were added 1a (0.327g, 1 mmol), 2-propyn-1-ol (0.112 g, 0.12 mL, 2 mmol) and Et3N (0.8 mL). The mixture was stirred for the time indicated in Table [1] , treated with NH4Cl saturated solution (5 mL) and then extracted with ethyl acetate. The organic layer was washed with brine and dried over MgSO4. The solvent was evaporated and the residue was purified by flash silica-gel chromatography eluted with hexane/ethyl acetate (7:3) to yield 2b in 81% yield (0.16 g). 1H NMR (200 MHz, CDCl3) δ 6.09 (s, 1 H), 4.39(s, 2 H), 2.26 (s, 3 H), 2.06 (t, J = 7.0 Hz, 2 H,), 1.98 (s, 1 H), 1.43 (quint, J = 7.0 Hz, 2 H), 1.23-1.17 (m, 4 H), 0.88 (t, J = 6.5 Hz, 3 H); 13C NMR (50 MHz, CDCl3) δ 134.51, 119.35, 94.97, 83.48, 51.54, 36.82, 31.03, 28.08, 22.35, 16.77, 13.92; IR (neat, cm-1) ν 3363, 2921, 2214, 1660, 1436; LRMS (rel. int.) m/z 198 (30), 180 (44), 151 (100), 133 (17), 71 (83), 47 (38).