Synthesis of N−H Bearing Imidazolidinones and Dihydroimidazolones Using Aza‐Heck Cyclizations

• Published in: Angewandte Chemie International Edition Vol. 57; no. 37; pp. 12081 - 12085
• Main Authors: Xu, Feiyang, Shuler, Scott A., Watson, Donald A.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 10-09-2018
• Edition: International ed. in English
• Subjects: Alkenes; aza-Heck reaction; catalysis; Chemical synthesis; dihydroimidazolones; Functional groups; imidazolidinones; Palladium; imidazolidinones; catalysis; palladium; aza-Heck reaction; dihydroimidazolones
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201806295

The synthesis of unsaturated, unprotected imidazolidinones via an aza‐Heck reaction is described. This palladium‐catalyzed process allows for the cyclization of N‐phenoxy ureas onto pendant alkenes. The reaction has broad functional group tolerance, can be applied to complex ring topologies, and can be used to directly prepare mono‐ and bis‐unprotected imidazolidinones. By addition of Bu4NI, dihydroimidazolones can be accessed from the same starting materials. Improved conditions for preparing unsaturated, unprotected lactams are also reported.
A palladium‐catalyzed process gives access to unsaturated, unprotected imidazolidinones through the cyclization of N‐phenoxy ureas onto pendant alkenes. The reaction has broad functional group and substrate tolerance and allows access to doubly unprotected imidazolidinones. By addition of Bu4NI, dihydroimidazolones can be accessed from the same starting materials.