Iron-Catalyzed Intramolecular C–H Amination of α-Azidyl Amides

Abstract

Iron-catalyzed intramolecular C−H amination of aliphatic azides has recently emerged as a powerful tool for the preparation of nitrogen heterocycles. This paper reports that α-azidyl amides can be converted in high efficacy to imidazolinone compounds via intramolecular C(sp 3 )−H amination by the action of a simple catalytic system composed of FeCl 2 and a β-diketiminate ligand. The reactions provide a simple and atom-economical approach toward polysubstituted imidazolinones.

DFT Mechanistic Account for the Site Selectivity of Electron-Rich C(sp3)–H Bond in the Manganese-Catalyzed Aminations

“…The bioinspired C–H aminations via nitrene insertion have attracted extensive research effort. , Typically, the aminations were performed with aminating reagents (e.g., organic azides and iminoiodinanes) as nitrene sources and metalloporphyrins or analogues as catalysts. − As illustrated by Scheme A, this type of amination generally undergoes three stages among which the C–H cleavage proceeds via hydrogen atom transfer (HAT) and prefers functionalizing the C–H with smaller bond dissociation energy (BDE). , To broaden its applications, it is highly desirable to develop new methods with distinct site selectivity.…”

Tricyclic Imidazolidin-4-ones by Witkop Oxidation of Tetrahydro-β-carbolines

“…5 We anticipate that these compounds will be a useful new chemotype for organic and medicinal chemistry. 27,28 ■ EXPERIMENTAL SECTION Melting points are uncorrected. 1D 1 H and 13 C NMR spectra were recorded on 400, 500, and 600 MHz spectrometers using CDCl 3 or DMSO-d 6 as solvents.…”

“…These benzannulated medium-ring keto imidazolidin-4-ones expand the menu of tetrahydro-β-carboline oxidation products beyond oxindoles and quinolones . We anticipate that these compounds will be a useful new chemotype for organic and medicinal chemistry. , …”

Synthesis of Sultams and Cyclic N-Sulfonyl Ketimines via Iron-Catalyzed Intramolecular Aliphatic C–H Amidation

“…Consequently, benzosultams 2o and 2p were obtained in moderate yields. Whereas the iron–nitrenoid insertion of aliphatic C­(sp 3 )–H bond is challenging, ,,, our catalytic system was shown to enable the reaction of such inert substrates ( 2r – 2t ). The reactions of tertiary ( 1r ) and secondary ( 1s ) C­(sp 3 )–H bonds delivered sultams 2r and 2s in 68% and 74% yields, respectively.…”

“…The last decades have seen the notable progress in the formation of C–N bonds via metal–nitrenoid C–H insertion reactions. − A number of efficient methods have been established utilizing both precious metals (i.e., Rh, − Ru, , Ir, , Ag) and base metals (i.e., Fe, Co, − Cu, , Mn − ) as the catalysts. However, such a strategy in the synthesis of sultams has thus far not been explored, and there are only a handful of examples known to date. , Pioneering work by Dawson and Breslow, and more recently by the Arnold, , Fasan, , and Hartwig groups, resulted in successful construction of benzosultams by intramolecular enzymatic C–H aminations with arylsulfonyl azides (Scheme a).…”