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Synlett 2002(11): 1904-1906
DOI: 10.1055/s-2002-34903
LETTER
© Georg Thieme Verlag Stuttgart · New York

Stille Reaction on Pyridinium Cations

Domingo García-Cuadrado, Ana M. Cuadro, Julio Alvarez-Builla, Juan J. Vaquero*
Departamento de Química Orgánica, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain
Fax: +34(91)8854686; e-Mail: juanjose.vaquero@uah.es;
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Publication History

Received 5 September 2002
Publication Date:
21 October 2002 (online)

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Abstract

A novel unit based on pyridinium cations has been synthesized by the Stille reaction and represents a model for development of molecular electronic devices.

Key words

heteroaromatic cations - Stille reaction - molecular electronic devices

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Representative Procedure A: A flame-dried two-necked flask was charged under argon with the pyridinium salt
(100 mg, 0.333 mmol) in dry DMF (5 mL). Then, 10 mol% CuI (0.033 mmol, 6.3 mg) and the corresponding stannane (1.3 equiv, 0.429 mmol) were slowly added followed by
5 mol% Pd(PPh3)4 (0.0165 mmol, 15.1 mg). The reaction mixture was heated at 80 ºC or stirred at r.t. (as indicated) and then filtered through a small pad of celite and washed with methanol. The solvent was removed and the residue was triturated with EtOAc. Purification of the crude product by column chromatography on silica gel (reverse phase), using water as the eluent yielded the coupling product.

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Representative Procedure B: A flame-dried two-necked flask was charged under argon with the pyridinium salt (100 mg, 0.333 mmol) in dry DMF (5 mL). Then, 5 mol% Pd2(dba)3 (0.0165 mmol, 15.1 mg) and 5 mol% P(o-Tol)3 (0.0165 mmol, 5 mg) were slowly added followed by the corresponding stannane (1.3 equiv, 0.429 mmol). The mixture was stirred at r.t. and the work-up procedure, which was similar to Method A, yielded the coupling product.

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Representative Procedure C: A flame-dried two-necked flask was charged under argon with the pyridinium salt (100 mg, 0.333 mmol) in dry DMF (5 mL). Then, 5 mol% Pd2(dba)3 (0.0165 mmol, 15.1 mg), 5 mol% P(o-Tol)3 (0.0165 mmol, 5 mg) and 1.3 equiv KF (0.429 mmol, 24.9 mg) were slowly added followed by 1.3 equiv of the corresponding stannane (0.429 mmol). The reaction mixture was heated at 80 ºC (as indicated), the residue was triturated with acetonitrile and the liquid was purified by column chromatography on silica gel (reverse phase) using water as the eluent.