Palladium-Catalyzed, Asymmetric Mizoroki–Heck Reaction of Benzylic Electrophiles Using Phosphoramidites as Chiral Ligands

We report herein the first examples of asymmetric Mizoroki–Heck reactions using benzyl electrophiles. A new phosphoramidite was identified to be an effective chiral ligand in the palladium–catalyzed reaction. The reaction is compatible with polar functional groups and can be readily scaled up. Several cyclic olefins worked well as olefin components. Thirty-one examples are included

<i>N</i>,<i>N</i>‑Dimethylformamide as Hydride Source in Nickel-Catalyzed Asymmetric Hydrogenation of α,β-Unsaturated Esters

Asymmetric transfer hydrogenation of α,β-unsaturated esters is realized by using a nickel/bisphosphine catalyst and N,N-dimethylformamide (DMF) as the hydride source

<i>N</i>,<i>N</i>‑Dimethylformamide as Hydride Source in Nickel-Catalyzed Asymmetric Hydrogenation of α,β-Unsaturated Esters

Asymmetric transfer hydrogenation of α,β-unsaturated esters is realized by using a nickel/bisphosphine catalyst and <i>N</i>,<i>N</i>-dimethylformamide (DMF) as the hydride source

Intermolecular, Catalytic Asymmetric Hydroamination of Bicyclic Alkenes and Dienes in High Yield and Enantioselectivity

Intermolecular, Catalytic Asymmetric Hydroamination of Bicyclic Alkenes and Dienes in High Yield and Enantioselectivit

Intermolecular, Catalytic Asymmetric Hydroamination of Bicyclic Alkenes and Dienes in High Yield and Enantioselectivity

Intermolecular, Catalytic Asymmetric Hydroamination of Bicyclic Alkenes and Dienes in High Yield and Enantioselectivit

Cross-Couplings of Unactivated Secondary Alkyl Halides: Room-Temperature Nickel-Catalyzed Negishi Reactions of Alkyl Bromides and Iodides

The development of a nickel- or palladium-catalyzed method for cross-coupling unactivated secondary alkyl halides has been a long-standing challenge in synthetic chemistry. This communication describes a simple catalyst system-Ni(cod)2/s-Bu-Pybox-that achieves room-temperature Negishi reactions of an array of functionalized primary and secondary alkyl bromides and iodides

Palladium-Catalyzed, Asymmetric Mizoroki–Heck Reaction of Benzylic Electrophiles Using Phosphoramidites as Chiral Ligands

We report herein the first examples of asymmetric Mizoroki–Heck reactions using benzyl electrophiles. A new phosphoramidite was identified to be an effective chiral ligand in the palladium–catalyzed reaction. The reaction is compatible with polar functional groups and can be readily scaled up. Several cyclic olefins worked well as olefin components. Thirty-one examples are included

Suzuki Cross-Couplings of Unactivated Secondary Alkyl Bromides and Iodides

The capacity to employ unactivated alkyl electrophiles as coupling partners will markedly increase the already exceptional utility of metal-catalyzed cross-coupling processes. This communication describes the development of a method that achieves the first Suzuki reactions of unactivated secondary alkyl bromides and iodides. The ability to couple readily available, easy-to-handle boronic acids is an attractive feature of this catalyst system

An Enantioselective, Intermolecular α-Arylation of Ester Enolates To Form Tertiary Stereocenters

In transition-metal catalyzed, asymmetric α-arylation of carbonyl compounds, formation of tertiary centers with high enantioselectivity is a longstanding problem, due to easy enolization of the monoarylation products. Herein, we report such examples using a palladium catalyst supported by a new, (R)-H8-BINOL-derived monophosphine. Silyl ketene acetals, together with a weakly basic activator, were used as equivalents of ester anions, and they reacted smoothly with aryl triflates in excellent enantiomeric excess (ee). The usefulness of the reaction was demonstrated in a gram-scale synthesis of (S)-Naproxen in 92% ee

N−H Activation of Hydrazines by Iridium(I). Double N−H Activation To Form Iridium Aminonitrene Complexes

Iridium(I) complexes of aromatic (PCP) and aliphatic (DtBPP) pincer ligands undergo single cleavage of the N−H bonds of hydrazine derivatives to form hydrazido complexes and geminal double cleavage to form unusual late transition metal aminonitrene complexes. In some cases, the cleavage of the N−N bond in the hydrazine is also observed. Oxidative additions of the N−H bonds of benzophenone hydrazone and 1-aminopiperidine to iridium(I) complexes give the corresponding hydridoiridium(III) hydrazido complexes within minutes. The complex containing an aromatic pincer ligand, (PCP)Ir(H)(NHNC5H10), slowly undergoes a second N−H bond cleavage at the α-N−H bond and elimination of hydrogen to generate an aminonitrene complex and dihydrogen in high yield. The reactions of the (PCP)Ir(I) fragment containing an aromatic pincer ligand with methyl-substituted hydrazines form a mixture of aminonitrene complexes, isocyanide iridium(III) dihydride complexes, and ammonia. The latter two products are likely formed by initial oxidative addition of the methyl C−H bond and the subsequent N−N bond cleavage. Reactions of the aminonitrene complex with CO or reagents that undergo oxidative addition (MeI and PhOH) lead to release of the “isodiazine” fragment to give tetrazene and tetrazine derivatives