Controlled Hydrosilylation of Carbonyls and Imines Catalyzed by a Cationic Aluminum Alkyl Complex

The synthesis, characterization, and unprecedented catalytic activity of cationic aluminum alkyl complexes toward hydrosilylation are described. X-ray crystallographic analysis of Tp*AlMe₂ (<b>1</b>) and [Tp*AlMe][I₃] (<b>3</b>) revealed the preference of Al for a tetrahedral coordination environment and the versatility of the Tp* ligand in stabilizing Al in bi- and tridentate coordination modes. [Tp*AlMe][MeB(C₆F₅)₃] (<b>2</b>) is highly active toward the hydrosilylation of a wide variety of carbonyls and imines, thus providing an inexpensive and versatile alternative to late transition metal catalysts

Controlled Hydrosilylation of Carbonyls and Imines Catalyzed by a Cationic Aluminum Alkyl Complex

The synthesis, characterization, and unprecedented catalytic activity of cationic aluminum alkyl complexes toward hydrosilylation are described. X-ray crystallographic analysis of Tp*AlMe₂ (<b>1</b>) and [Tp*AlMe][I₃] (<b>3</b>) revealed the preference of Al for a tetrahedral coordination environment and the versatility of the Tp* ligand in stabilizing Al in bi- and tridentate coordination modes. [Tp*AlMe][MeB(C₆F₅)₃] (<b>2</b>) is highly active toward the hydrosilylation of a wide variety of carbonyls and imines, thus providing an inexpensive and versatile alternative to late transition metal catalysts

Nitrene Metathesis and Catalytic Nitrene Transfer Promoted by Niobium Bis(imido) Complexes

We report a metathesis reaction in which a nitrene fragment from an isocyanide ligand is exchanged with a nitrene fragment of an imido ligand in a series of niobium bis­(imido) complexes. One of these bis­(imido) complexes also promotes nitrene transfer to catalytically generate asymmetric dialkylcarbodiimides from azides and isocyanides in a process involving the Nb­(V)/Nb­(III) redox couple

Asymmetric Synthesis of α‑Branched Amines via Rh(III)-Catalyzed C–H Bond Functionalization

The first asymmetric intermolecular addition of non-acidic C–H bonds to imines is reported. The use of the activating <i>N</i>-perfluorobutanesulfinyl imine substituent is essential for achieving sufficient reactivity and provides outstanding diastereoselectivity (>98:2 dr). Straightforward removal of the sulfinyl group with HCl yields the highly enantiomerically enriched amine hydrochlorides

Dis-assembly of a Benzylic CF₃ Group Mediated by a Niobium(III) Imido Complex

All three C–F bonds in CF₃-substituted arenes are activated by a niobium imido complex, driven by the formation of strong Nb–F bonds. The mechanism of this transformation was studied by NMR spectroscopy, which revealed the involvement of Nb­(III). Attempts to extend this chemistry to nonaromatic CF₃ groups led to intramolecular reactivity

Rhodium-Catalyzed Synthesis of Branched Amines by Direct Addition of Benzamides to Imines

Rhodium-catalyzed addition of benzamide C–H bonds to a range of aromatic <i>N</i>-sulfonyl aldimines has been developed and proceeds with high functional group compatibility. The synthetic utility of the resulting branched amine products has also been demonstrated by the preparation of isoindoline and isoindolinone frameworks

Oxygen Atom Transfer and Intramolecular Nitrene Transfer in a Rhenium β‑Diketiminate Complex

We present two routes to the oxo rhenium complex OReCl₂(BDI) (<b>1</b>) (BDI = <i>N</i>,<i>N</i>′-bis­(2,6-diisopropylphenyl)-β-diketiminate) and discuss the properties and reactivity of this material. Several adducts of <b>1</b> with DMAP (<b>1-DMAP</b>; DMAP = 4-dimethylaminopyridine), isonitriles (<b>1-XylNC</b>; XylNC = 2,6-dimethylphenyl isocyanide), and phosphines (<b>1-PEt</b>_<b>3</b>; PEt₃ = triethylphosphine) were isolated and characterized. Additionally, to probe the ancillary limitations of the BDI framework in high-valent rhenium complexes, oxygen atom transfer (OAT) reactivity with <b>1</b> was pursued. It was found that under thermolysis conditions OAT between <b>1</b> and PEt₃ was observed by NMR spectroscopy, which indicated the formation of a new species, (ArN)­ReCl₂­(MAD)­(PEt₃) (<b>2</b>; Ar = 2,6-diisopropylphenyl, MAD = 4-((2,6-diisopropylphenyl)­imino)­pent-2-enide). A mechanism for the generation of <b>2</b> involving nitrene transfer to rhenium from the BDI ligand is proposed. X-ray crystal structures of complexes <b>1</b>, <b>1-PEt</b>_<b>3</b>, <b>1-DMAP</b>, and <b>2</b> were determined and are discussed in detail

Oxygen Atom Transfer and Intramolecular Nitrene Transfer in a Rhenium β‑Diketiminate Complex

We present two routes to the oxo rhenium complex OReCl₂(BDI) (<b>1</b>) (BDI = <i>N</i>,<i>N</i>′-bis­(2,6-diisopropylphenyl)-β-diketiminate) and discuss the properties and reactivity of this material. Several adducts of <b>1</b> with DMAP (<b>1-DMAP</b>; DMAP = 4-dimethylaminopyridine), isonitriles (<b>1-XylNC</b>; XylNC = 2,6-dimethylphenyl isocyanide), and phosphines (<b>1-PEt</b>_<b>3</b>; PEt₃ = triethylphosphine) were isolated and characterized. Additionally, to probe the ancillary limitations of the BDI framework in high-valent rhenium complexes, oxygen atom transfer (OAT) reactivity with <b>1</b> was pursued. It was found that under thermolysis conditions OAT between <b>1</b> and PEt₃ was observed by NMR spectroscopy, which indicated the formation of a new species, (ArN)­ReCl₂­(MAD)­(PEt₃) (<b>2</b>; Ar = 2,6-diisopropylphenyl, MAD = 4-((2,6-diisopropylphenyl)­imino)­pent-2-enide). A mechanism for the generation of <b>2</b> involving nitrene transfer to rhenium from the BDI ligand is proposed. X-ray crystal structures of complexes <b>1</b>, <b>1-PEt</b>_<b>3</b>, <b>1-DMAP</b>, and <b>2</b> were determined and are discussed in detail

Asymmetric Synthesis of α‑Branched Amines via Rh(III)-Catalyzed C–H Bond Functionalization

The first asymmetric intermolecular addition of non-acidic C–H bonds to imines is reported. The use of the activating <i>N</i>-perfluorobutanesulfinyl imine substituent is essential for achieving sufficient reactivity and provides outstanding diastereoselectivity (>98:2 dr). Straightforward removal of the sulfinyl group with HCl yields the highly enantiomerically enriched amine hydrochlorides

Oxygen Atom Transfer and Intramolecular Nitrene Transfer in a Rhenium β‑Diketiminate Complex

We present two routes to the oxo rhenium complex OReCl₂(BDI) (<b>1</b>) (BDI = <i>N</i>,<i>N</i>′-bis­(2,6-diisopropylphenyl)-β-diketiminate) and discuss the properties and reactivity of this material. Several adducts of <b>1</b> with DMAP (<b>1-DMAP</b>; DMAP = 4-dimethylaminopyridine), isonitriles (<b>1-XylNC</b>; XylNC = 2,6-dimethylphenyl isocyanide), and phosphines (<b>1-PEt</b>_<b>3</b>; PEt₃ = triethylphosphine) were isolated and characterized. Additionally, to probe the ancillary limitations of the BDI framework in high-valent rhenium complexes, oxygen atom transfer (OAT) reactivity with <b>1</b> was pursued. It was found that under thermolysis conditions OAT between <b>1</b> and PEt₃ was observed by NMR spectroscopy, which indicated the formation of a new species, (ArN)­ReCl₂­(MAD)­(PEt₃) (<b>2</b>; Ar = 2,6-diisopropylphenyl, MAD = 4-((2,6-diisopropylphenyl)­imino)­pent-2-enide). A mechanism for the generation of <b>2</b> involving nitrene transfer to rhenium from the BDI ligand is proposed. X-ray crystal structures of complexes <b>1</b>, <b>1-PEt</b>_<b>3</b>, <b>1-DMAP</b>, and <b>2</b> were determined and are discussed in detail