Nucleophilic addition of sulfonamides to 1-bromo-1-alkynes provided (Z)-N-(1-bromo-1-alken-2-yl)-p-toluenesulfonamides in good yield and in a highly regio- and stereoselective manner. Treatment of product (Z)-N-(1-bromo-1-octen-2-yl)-N-allyl-p-toluenesulfonamide with a palladium catalyst under Heck conditions afforded 1-(p-toluenesulfonyl)-2-hexyl-4-methylpyrrole in good yield. Other pyrroles with various substituents can also be prepared in good yield by this method.

Bromine as a double agent: The bromine atom in 1-bromo-1-alkynes works as an electron-withdrawing group to effect the nucleophilic addition of sulfonamides. It again plays a pivotal role in the palladium-catalyzed cyclization of the resultant (Z)-2-(sulfonylamino)-1-bromoalkenes into nitrogen heterocycles (see scheme).

Nucleophilic addition of imidazolines to 1-halo-1-alkynes takes place by simple heating in DMF without any additives to give (Z)-N-(1-halo-1-alken-2-yl)imidazolines in good yield and in a highly regio- and stereoselective manner. These reaction conditions are also valid for the similar addition of imidazoles.

Brom in der Doppelrolle: Das Bromatom in 1‐Brom‐1‐alkinen fungiert als elektronenziehende Gruppe, um die nukleophile Addition von Sulfonamiden zu bewirken. Auch bei der anschließenden Palladium‐katalysierten Cyclisierung der entstehenden (Z)‐2‐(Sulfonylamino)‐1‐bromalkene zu Stickstoffheterocyclen spielt es eine entscheidende Rolle (siehe Schema).

General. 1 H and 13 C NMR spectra were taken on an Agilent 400-MR spectrometer at 400 and 100 MHz. CDCl 3 was used as the solvent unless otherwise noted. Chemical shifts are reported in parts per million shift (δ value) from Me 4 Si (δ 0 ppm for 1 H) or based on the middle peak of the solvent (CDCl 3) (δ 77.00 ppm for 13 C) as an internal standard. Signal patterns are indicated as br, broad; s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet. Coupling constants (J) are given in Hertz. When yields were determined by 1 H NMR spectroscopy, a known amount of trichloroethylene was added as an internal standard. Infrared (IR) spectra were recorded on a JASCO A-100 spectrometer and are reported in wave numbers (cm-1). High resolution mass spectra (HRMS) were obtained on a Bruker micrOTOF by the positive electrospray ionization (ESI) method calibrated with sodium formate or on a JEOL JMS-700 by the fast atom bombardment (FAB) method (matrix: m-nitrobenzyl alcohol (NBA)) calibrated with perfluoropolyether or by the electron ionization (EI) method calibrated with perfluorokerosene at the Suzukake-dai Material Analysis Center, Technical Department, Tokyo Institute of Technology. Column chromatography was performed with silica gel [Wakogel® R-200, size 100-200 mesh (75-150 μm), Cat. No. 233-00077, Wako Pure Chemical Industries, Ltd. (Japan)]. Dry solvents (THF, CH 2 Cl 2 , and DMF) were purchased from Kanto Chemicals Co. (Japan). K 3 PO 4 was purchased from Koso Chemical Co. (Japan). Chemicals were purified or dried in a standard manner, if necessary. 1-Chloro-1-octyne (1). Starting haloacetylene for 8.