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Synthesis 2008(10): 1570-1574  
DOI: 10.1055/s-2008-1072567
PAPER
© Georg Thieme Verlag Stuttgart · New York

Catalytic Aminohalogenation Reaction of β-Nitrostyrenes with N,N-Dichloro-p-toluenesulfonamide Resulting in Dichlorinated Haloamides with Opposite Regiochemistry to Previous Systems

Sanjun Zhia, Jianlin Hana, Chen Lina, Guanghui Ana, Yi Pan*a,b, Guigen Li*c
a School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. of China
b State Key Lab of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. of China
e-Mail: yipan@nju.edu.cn;
c Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
e-Mail: guigen.li@ttu.edu;
Further Information

Publication History

Received 23 December 2007
Publication Date:
27 March 2008 (online)

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Abstract

Reaction of β-nitrostyrenes with N,N-dichloro-p-tolu­enesulfonamide (TsNCl2) has been successfully conducted by using either copper(I) chloride or 4-dimethylaminopyridine (DMAP) as the catalyst. The reaction resulted in dichlorohaloamine products with the opposite regiochemistry to that previously observed. In the presence of DMAP, the reaction proceeded smoothly to completion within 24 hours at room temperature and gave good chemical yields (65-88%). The structure of one of the products was confirmed by X-ray crystal structure analysis. This reaction is proposed to occur through a new mechanism involving a chloronium intermediate.

Key words

aminohalogenation - β-nitrostyrenes - N,N-dichloro-p-toluenesulfonamide - 4-dimethylaminopyridine

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X-ray crystal data for 3b. CCDC 656501; empirical formula: C16H16Cl2N2O4S; formula weight: 403.27; crystal color: colorless; crystal dimensions: 0.3 × 0.26 × 0.24 mm; Crystal system: orthorhombic; lattice parameter: a = 7.748 (5) Å, b = 19.85 (1) Å, c = 23.03 (1) Å; V = 3542 (3) Å3; space group: Pbca; Z = 8; D(calculated) = 1.512 g/cm3; F000 = 1664; diffractometer: Bruker Smart Apex CCD area detector; residuals: R, Rw: 0.064, 0.148.

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In our previous catalytic aminohalogenation processes (see ref. 18a), amino functionality was normally added onto the β-position of the substrates that are attached by electron-withdrawing groups, such as ester, ketone or nitrile.