Synlett 2002(5): 0832-0834
DOI: 10.1055/s-2002-25362
LETTER
© Georg Thieme Verlag Stuttgart · New York

Palladium-catalyzed Formation of Heterocycles by Coupling of Dibromoarenes and Sulfoximines

Carsten Bolm*, Marc Martin, Laura Gibson
Institut für Organische Chemie der RWTH Aachen, Professor-Pirlet-Str. 1, 52056 Aachen, Germany
Fax: +49(241)8092391; e-Mail: Carsten.Bolm@oc.RWTH-Aachen.de;
Further Information

Publication History

Received 5 March 2002
Publication Date:
07 February 2007 (online)

Abstract

The palladium-catalyzed reaction between dibromo­arenes and sulfoximines affords 6 to 8-membered heterocycles in excellent yields. The reaction sequence involves an intermolecular N-arylation followed by an intramolecular ring closure.

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Bolm, C.; Martin, M.; SimiÊ, O.; Verrucci, M., submitted for publication.

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In a typical experiment [Pd2(dba)3] (36.0 mg, 0.04 mmol) and rac-BINAP (50.0 mg, 0.08 mmol) were dissolved in 20 mL of toluene under an argon atmosphere and refluxed for 10 min. After cooling of the resulting red solution to room temperature, NaO-tBu (384 mg, 4.06 mmol), sulfoximine 1a (776.0 mg, 5.0 mmol), and 2,2′-dibromobiphenyl (312.0 mg, 1.0 mmol) were added and stirring was continued under reflux for an additional 20 h. The suspension was diluted with diethyl ether at room temperature and filtered through a plug of celite. After removing the volatile compounds, the product was directly purified by column chromatography (silica, pentane-ethyl acetate 3:1, Rf = 0.49) furnishing 7a (300 mg, 0.98 mmol, 98%) as a colorless solid, which could be crystallized in ethyl acetate. Mp: 229 °C; [α]D = +62.6
(c = 1, CHCl3). 1H NMR (400 MHz, CDCl3): δ 4.27 (d, J = 15 Hz, 1 H, CH a Hb), 4.44 (d, J = 15 Hz, 1 H, CHa H b ), 6.68 (d, J = 8 Hz, 1 H, CH aryl ), 7.15-7.65 (m, 13 H, CH aryl ).
13C NMR (100 MHz, CDCl3): δ 58.5, 123.3, 127.0, 127.8, 128.4, 128.7, 129.1, 129.7, 129.8, 130.1, 133.5, 135.7, 140.0, 142.3. MS: m/z (%) 305 (M+, 24), 180(100), 152(28). IR (KBr): 685, 724, 768, 782, 810, 872, 995, 1018, 1026, 1109, 1144, 1176, 1206, 1240, 1258, 1281, 1434, 1445, 1475, 1592, 2906, 2972, 3054, 3099 cm-1. Anal. calcd for C19H15NOS: C, 74.73; H, 4.95; N, 4.59; found: C, 74.76;
H, 5.06; N, 4.54.

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Unless indicated otherwise, [Pd2(dba)3] was used as the catalyst.

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Isolated 1-bromo-2-N-[S-methyl-S-phenylsulfonimidoyl]-benzene also did not cyclize when subjected to the typical coupling conditions described in ref. [9]