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Synlett 2006(14): 2290-2292  
DOI: 10.1055/s-2006-949638
LETTER
© Georg Thieme Verlag Stuttgart · New York

Comparison of Copper(II) Acetate Promoted N-Arylation of 5,5-Dimethyl Hydantoin and Other Imides with Triarylbismuthanes and Aryl Boronic Acids

Helmut M. Hügel*, Colin J. Rix, Karin Fleck
School of Applied Sciences (Applied Chemistry), RMIT University, GPO Box 2476V, Melbourne, Victoria 3001, Australia
Fax: +61(3)99253747; e-Mail: helmut.hugel@rmit.edu.au;
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Publication History

Received 12 June 2006
Publication Date:
24 August 2006 (online)

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Abstract

This work demonstrates that the copper acetate promoted N-arylation of imides with boronic acids can be employed as a ­major method for the synthesis of N3-aryl hydantoins.

Key words

arylations - imides - hydantoins - organoboron chemistry - organometallic reagents

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General Procedure: Imide (2.1 mmol), Cu(OAc)2 (2.0 mmol, 0.38 g), 4 Å molecular sieves (750 mg crushed in a mortar) and triarylbismuthane or arylboronic acid (2.5 mmol) were combined in a Schlenk flask (100 mL) and anhyd CH2Cl2 (50 mL) and pyridine (0.2 mL) were added. The flask was flushed with pure oxygen for 5 min, sealed (glass stopper tightened with Teflon ring) and the reaction mixture stirred for 7 d (TLC monitor) during which time the blue colour of the Cu(OAc)2 turned green. The solution was filtered through celite and thoroughly extracted with CH2Cl2 (3 × 50 mL) and EtOAc (3 × 50 mL). The solvent was re-moved in vacuo. The residue was mixed with, and impreg-nated on, silica gel, and then separated via flash column chromatography (hexane-EtOAc; 4:1 for phthalimide deri-vatives; 2:3 for succinimide and 5,5′-dimethylhydantoin derivatives).