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Synlett 2005(17): 2631-2634  
DOI: 10.1055/s-2005-918934
LETTER
© Georg Thieme Verlag Stuttgart · New York

Copper-Catalyzed Cross- and Carbonylative Coupling Reactions of ­Alkynyliodonium Salts with Organoboronic Acids and Organostannanes

Chan-Mo Yu*, Jae-Hong Kweon, Pil-Su Ho, Sin-Cheol Kang, Gong Yeal Lee
Department of Chemistry and Institute of Basic Sciences, Sungkyunkwan University, Suwon 440-746, Korea
Fax: +82(31)2907075; e-Mail: cmyu@chem.skku.ac.kr;
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Publication History

Received 18 July 2005
Publication Date:
05 October 2005 (online)

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Abstract

Copper-catalyzed cross- and carbonylative coupling ­reactions have been achieved in the reaction of a variety of alkynyl­iodonium salts with arylboronic acids and organostannanes under the mild reaction conditions in high yield. Our investigation shows that the alkynylidonium tetrafluoroborates are more efficient than those of triflates and tosylates.

Key words

copper catalyst - iodonium salt - organoboronic acid - coupling - organostannane

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Typical Procedure for the Synthesis of 3a.
A flame-dried flask containing CuI (7.6 mg, 0.04 mmol), K2CO3 (133 mg, 0.96 mmol), and PhB(OH)2 (2a, 107 mg, 0.88 mmol) was evacuated and carefully purged with N2 and then charged with freshly purified mixed solvent (4 mL, DME-DMF-H2O, 3:1:1). After stirring at 20 °C for 10 min, 1a (297 mg, 0.8 mmol) in a mixed solvent (2 mL) was added over 10 min to the resulting mixture. After stirring at 20 °C for 1 h, the resulting mixture was quenched by addition of a 10% aq NH4Cl (5 mL) solution, and then extracted with Et2O (3 ×). The combined organics were washed with H2O (1 ×) and brine (1 ×). The organic layer was dried over anhyd MgSO4, filtered, and concentrated under reduced pressure. The crude product was purified by flash column chromatography (EtOAc-hexane, 1:15) to give 3a (115 mg, 0.727 mmol, 91%) as a colorless liquid.

15

Typical Procedure for the Synthesis of 5a.
A flame-dried Schlenk flask containing CuI (7.6 mg, 0.04 mmol), K2CO3 (133 mg, 0.96 mmol), and PhB(OH)2 (2a, 107 mg, 0.88 mmol) was evacuated and carefully purged with CO three times using a balloon and then charged with a mixed solvent (freshly purified and degassed, 4 mL, DME-H2O, 4:1). After stirring at 20 °C for 10 min, 1a (297 mg, 0.8 mmol) in a mixed solvent (2 mL) was added over 10 min. Reaction was allowed to proceed for an additional 2 h. After removal of CO balloon carefully, the resulting mixture was quenched by addition of a 10% aq NH4Cl (5 mL) solution, and then extracted with Et2O (3 ×). The combined organics were washed with H2O (1 ×) and brine (1 ×). The organic layer was dried over anhyd MgSO4, filtered, and concentrated under reduced pressure. The crude product was purified by flash column chromatography (EtOAc-hexane, 1:10) to give 5a (124 mg, 0.67 mmol, 83%) as a colorless liquid.