Synthesis 2020; 52(14): 2099-2105
DOI: 10.1055/s-0040-1707103
paper
© Georg Thieme Verlag Stuttgart · New York

A Straightforward Synthesis of N-Substituted Ureas from Primary Amides

Nathalie Saraiva Rosa
a   Normandie Univ, ENSICAEN, UNICAEN, CNRS, LCMT, 14000 Caen, France   eMail: vincent.reboul@ensicaen.fr
,
a   Normandie Univ, ENSICAEN, UNICAEN, CNRS, LCMT, 14000 Caen, France   eMail: vincent.reboul@ensicaen.fr
,
a   Normandie Univ, ENSICAEN, UNICAEN, CNRS, LCMT, 14000 Caen, France   eMail: vincent.reboul@ensicaen.fr
,
Jean-François Lohier
a   Normandie Univ, ENSICAEN, UNICAEN, CNRS, LCMT, 14000 Caen, France   eMail: vincent.reboul@ensicaen.fr
,
b   Normandie Univ, CNRS, UNIROUEN, INSA Rouen, COBRA, 76000 Rouen, France
,
a   Normandie Univ, ENSICAEN, UNICAEN, CNRS, LCMT, 14000 Caen, France   eMail: vincent.reboul@ensicaen.fr
› Institutsangaben
The authors thank the Centre National de la Recherche Scientifique (CNRS), Normandie Université (RIN ChemImaging), Labex SynOrg (Grant No. ANR-11-LABX-0029), the Conseil Régional de Normandie and the Fonds Européen de Développement Régional (FEDER) for financial support.
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Publikationsverlauf

Received: 13. Februar 2020

Accepted after revision: 06. April 2020

Publikationsdatum:
27. April 2020 (online)


Abstract

A direct and convenient method for the preparation of N-substituted ureas is achieved by treating primary amides with phenyliodine diacetate (PIDA) in the presence of an ammonia source (NH3 or ammonium carbamate) in MeOH. The use of 2,2,2-trifluoroethanol (TFE) as the solvent increases the electrophilicity of the hypervalent iodine species and allows the synthesis of electron-poor carboxamides. This transformation involves a nucleophilic addition of ammonia on the isocyanate intermediate generated in situ by a Hofmann rearrangement of the starting amide.

Supporting Information