Synlett 2011(7): 959-963  
DOI: 10.1055/s-0030-1259727
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Direct Arylation of Heteroarenes Catalyzed by a Palladium-1,10-Phenanthroline Complex

Ryo Takita*a,b, Daichi Fujitaa, Fumiyuki Ozawa*a
a International Research Center for Elements Science (IRCELS), Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
Fax: +81(774)383039; e-Mail: ozawa@scl.kyoto-u.ac.jp;
b Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
e-Mail: takita@mol.f.u-tokyo.ac.jp;
Further Information

Publication History

Received 10 December 2010
Publication Date:
10 March 2011 (online)

Abstract

A new entry in direct arylation of heteroarenes using Pd(OAc)2 and 1,10-phenanthroline as a nitrogen-based ligand is reported. The long induction period observed at the initial stage of the reaction was effectively reduced by modification of the catalyst preparation, leading to improved chemical yields (69-92%) and shortening of reaction times (3-10 h).

4

In this manuscript, the term ‘direct arylation of heteroarenes’ denotes the reaction of heteroarenes with (pseudo)halo-arenes. For other types of reactions (e.g., directing-group-controlled reactions or the reaction of arenes with organometallic reagents), see ref. 1.

16

Isolated Pd(OAc)2(1,10-phenanthroline) gave a comparable result (69%) under the same conditions.

17

The remaining part of 1a is very probably converted to benzene. The reduction of 1e to give ethyl benzoate was confirmed by GC-MS analysis of the reaction solution of entry 5 in Table  [²] .