Efficient Amination of Activated and Non‐Activated C(sp³)−H Bonds with a Simple Iron–Phenanthroline Catalyst

Abstract

A readily available catalyst consisting of iron dichloride in combination with 1,10‐phenanthroline catalyzes the ring‐closing C−H amination of N‐benzoyloxyurea to form imidazolidin‐2‐ones in high yields. The C−H amination reaction is very general and applicable to benzylic, allylic, propargylic, and completely non‐activated aliphatic C(sp3)−H bonds, and it also works for C(sp2)−H bonds. The surprisingly simple method can be performed under open flask conditions.

Iron-Catalyzed, Site-Selective Difluoromethylthiolation (−SCF2H) and Difluoromethylselenation (−SeCF2H) of Unactivated C(sp3)–H Bonds in N-Fluoroamides

“…(For details, see the SI.) On the basis of related reports , and these preliminary results, a proposed reaction mechanism is provided (Figure ). At the beginning, Fe­(II)­L n complex A and acetylacetonate anion B are formed via the reduction of the ligand-coordinated Fe­(III)­(acac) 3 upon heating .…”

Recent Advances in Nonprecious Metal Catalysis

“…A related report by Meggers and co-workers describes the synthesis of ureas via C−H amination of sp 3 and sp 2 C−H bonds of benzyloxyurea substrates using an iron phenantroline catalyst (Scheme 26). 66 The authors propose a similar mechanistic pathway as Chang and co-workers where an iron nitrenoid intermediate undergoes 1,5-hydrogen atom transfer followed by radical rebound to form the carbon−nitrogen bond. As expected based on this mechanism, formation of the 5-membered urea was favored over the 6-membered ring when multiple hydrogen atoms are available, and the ratio of isomers depends on the stereoelectronics of the C−H bonds.…”

Iron‐Catalyzed Intramolecular C—H Amidation of N‐Benzoyloxyureas

“…Herein, we reported an efficient Fe(OTf) 2 /bipyridine-catalyzed C-H amidation of N-benzoyloxyureas. [11] In this new transformation, both C(sp…”