Synthesis of Diarylamines in the Thiophene Series by Buchwald-Hartwig Coupling­

Abstract

We describe here the palladium-catalyzed amination of polysubstituted bromothiophenes under mild conditions (using Cs₂CO₃ as base). Anilines bearing electron-donating groups gave good results whereas anilines with electron-withdrawing substituents required greater catalyst loadings and gave lower yields.

palladium catalysis - amination - bromothiophenes - di­arylamines

References

Reviews :

1a Hartwig JF. Synlett  1997,  329 

1b Yang BH. Buchwald SL. J. Organomet. Chem.  1999,  576:  125 

Examples for the amination of other heteroaryl halides for coupling of halopyridines see:

2a Wagaw S. Buchwald SL. J. Org. Chem.  1996,  61:  7240 

2b Jonckers THM. Maes BUW. Lemière GLF. Dommisse R. Tetrahedron  2001,  57:  7027 

2c For coupling of chloroquinoline see: Jonckers THM. Maes BUW. Lemière GLF. Rombouts G. Pieters L. Haemers A. Dommisse R. Synlett  2003,  615 

2d For coupling of bromopyrrole see: Castellote I. Vaquero JJ. Alvarez-Builla J. Tetrahedron Lett.  2004,  45:  769 

2e For coupling of chlorobenzothiazole see: Hong Y. Tanoury GJ. Wilkinson HS. Bakale RP. Wald SA. Senanayake CH. Tetrahedron Lett.  1997,  38:  5607 

3 Yin J. Zhao MM. Huffman MA. McNamara JM. Org. Lett.  2002,  20:  3481 

4 Watanabe M. Yamamoto T. Nishiyama M. Chem. Commun.  2000,  133 

5 Ogawa K. Radke KR. Rothstein SD. Rasmussen SC. J. Org. Chem.  2001,  66:  9067 

6 Hooper MW. Utsunomiya M. Hartwig JF. J. Org. Chem.  2003,  68:  2861 

7 Luker TJ. Beaton HG. Whiting M. Mete A. Cheshire DR. Tetrahedron Lett.  2000,  41:  7731 

8 Sommen G. Comel A. Kirsch G. Synthesis  2003,  735 

9 Hesse S. Kirsch G. Tetrahedron Lett.  2002,  43:  1213 

10 Queiroz M.-JRP. Begouin A. Ferreira ICFR. Kirsch G. Calhelha RC. Barbosa S. Estevinho LM. Eur. J. Org. Chem.  2004,  3679 

11

Aminothiophenes were synthesized as described in ref. 7.

12 Doyle MP. Siegfried B. Dellaria JF. J. Org. Chem.  1977,  42:  2426