Synlett 2010(7): 1104-1106  
DOI: 10.1055/s-0029-1219566
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Synthesis of Symmetrical Ureas by (Diacetoxyiodo)benzene-Induced Hofmann Rearrangement

Dirk Landsberg, Markus Kalesse*
Institut für Organische Chemie, Leibniz Universität Hannover, Schneiderberg 1B, 30167 Hannover, Germany
Fax: +49(511)7623011; e-Mail: Markus.Kalesse@oci.uni-hannover.de;
Further Information

Publication History

Received 22 January 2010
Publication Date:
02 March 2010 (online)

Abstract

Amides undergo Hofmann rearrangement by treatment with (diacetoxyiodo)benzene (DAIB) to provide symmetrical ureas in a simple and robust transformation.

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Representative Procedure (Table 1, Entry 1): A solution of benzamide (121 mg, 1.00 mmol), PhI(OAc)2 (DAIB; 419 mg, 1.30 mmol) and H2O (54 µL, 3.00 mmol) in CH2Cl2 (10 mL) was stirred at ambient temperature for 16 h. The resulting solution was stirred at 40 ˚C for 1 h, then the solution was concentrated under vacuum and the remaining residue was purified by column chromatography on silica gel (hexane-EtOAc, 3:1) to yield the corresponding urea as a colorless solid (52.4 mg, 49%).