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Synlett 2011(17): 2555-2558  
DOI: 10.1055/s-0030-1260337
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

An Efficient Pd-Catalyzed Coupling of Hydrazine Derivatives with Aryl Halides

Fang-Fang Maa, Zhi-Yong Penga, Wan-Fang Lia, Xiao-Min Xiea, Zhaoguo Zhang*a,b
a School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, P. R. of China
Fax: +86(21)54748925; e-Mail: zhaoguo@sjtu.edu.cn;
b Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. of China
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Publication History

Received 19 July 2011
Publication Date:
27 September 2011 (online)

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Abstract

A convenient method for the intermolecular N-arylation of hydrazides with aryl halides in the presence of a palladium catalyst, a MOP-type ligand, and Cs2CO3 is reported. The reaction gives coupling products in good to excellent yields and has a high tolerance towards a wide spectrum of functional groups.

Key words

palladium - MOP ligands - aryl halide - N-aryl hydrazides - N-arylation

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General Procedure: An oven-dried Schlenk tube was evacuated and backfilled with nitrogen. The Schlenk tube was charged with [Pd(dba)2] (11.4 mg, 2.0 mmol% ), ligand (3.0 mmol%), mono- or di(t-butoxycarbonyl)hydrazine
(1.2 mmol), and base (1.5 mmol), and capped with a rubber septum. The Schlenk tube was evacuated and backfilled with nitrogen three times. To the Schlenk tube were added aryl halide (1.0 mmol) and solvent (4.0 mL). The septum was replaced with a Teflon screw-cap and the mixture was heated to 100 ˚C with stirring for 20 h. Then reaction mixture was allowed to cool to room temperature, diluted with ethyl acetate, filtered through Celite, and concentrated under reduced pressure. The crude material was purified by column chromatography on silica gel (ethyl acetate-hexanes, 1:1→1:20)