Iron(II)-Catalyzed Intermolecular Amino-Oxygenation of Olefins through the N–O Bond Cleavage of Functionalized Hydroxylamines

Abstract

An iron-catalyzed diastereoselective intermolecular olefin amino-oxygenation reaction is reported, which proceeds via an iron-nitrenoid generated by the N–O bond cleavage of a functionalized hydroxylamine. In this reaction, a bench-stable hydroxylamine derivative is used as the amination reagent and oxidant. This method tolerates a range of synthetically valuable substrates that have been all incompatible with existing amino-oxygenation methods. It can also provide amino alcohol derivatives with regio- and stereochemical arrays complementary to known amino-oxygenation methods.

Rhodium‐Catalyzed Alkene Difunctionalization with Nitrenes

“…In all cases, lowy ields or complex mixturesw ere obtained. Several solvents were also tested, including toluene, acetonitrile, trifluorotoluene, andi sopropyl acetate, but againo nly low yields or complex mixtures were observed( Ta ble 1, entries [10][11][12][13]. Dichloromethane also provedt ob ean efficients olventf or the reaction (82 %y ield of the oxyaminatedp roduct) and thus could be an alternative to benzene (Table 1, entry 9).…”

“…Similarly,m ost of the intermoleculard ia-minationr eactions involvet he addition of the same amino groups.A ccordingly,t he search forc onditions allowing the regioselectivei ntermolecular difunctionalization of alkenes remainsachallenge that has been successfully addressed in only al imited number of studies. [10,11] Catalytic nitrene-transfer reactions [12] have recentlye merged as an efficient method for 1,2-difunctionalization of alkenes. The intramolecular additions of nitrenesg enerated from carbamateso rs ulfamates in the presence of an iodine(III) oxidant and ad irhodium(II) complex allow for regioselectivet ransformationo fv ariousa lkenes, indolic substrates, and glycals into oxyamidated products in very good yields.…”

Practical Synthetic Procedures for the Iron-Catalyzed Intermolecular Olefin Aminohydroxylation Using Functionalized Hydroxylamines

“…Therefore, we explored a range of new amination reagents, iron catalysts, and ligands, and identified entirely new procedures for the intermolecular olefin aminohydroxylation (Scheme 2). 4 …”

Synthesis of 2-Aryl- and 2-Vinylpyrrolidines via Copper-Catalyzed Coupling of Styrenes and Dienes with Potassium β-Aminoethyl Trifluoroborates

“…40 Alternatively, the benzylic radical could be further oxidized by MnO 2 to provide a benzylic carbocation that is then trapped by the pendant amine (path II). 31 Oxidation of [Cu(I)] back to [Cu(II)] with MnO 2 then closes the catalytic cycle. At the onset of our mechanistic investigation, we could not differentiate between path I and path II because, based on oxidation potentials, MnO 2 is capable of oxidizing both [Cu(I)] and a benzylic radical, although [Cu(I)] is the more easily oxidized species.…”

“…26-31 The products of these reactions, by virtue of the required substrates, often contain additional functional groups (Schemes 1a and 1b) that may not be desired in all applications and primarily N -sulfonyl pyrrolidine synthesis has been reported.…”