C–P Bond-Forming Reactions via C–O/P–H Cross-Coupling Catalyzed by Nickel

Visible-Light-Induced Cascade Reaction of Isocyanides and N-Arylacrylamides with Diphenylphosphine Oxide via Radical C-P and C-C Bond Formation

An effective photoredox-mediated tandem phosphorylation/cyclization reaction of diphenylphosphine oxide with three types of radical acceptors leads to P(O)Ph₂-containing phenanthridines, isoquinolines, and indolin-2-ones by formation of both C-P and C-C bonds. [Ir(ppy)₂(dtbpy)]PF₆ (1 mol %) was used as the catalyst, CsF or Cs₂CO₃ as the base, and K₂S₂O₈ as the oxidant. A series of functional groups can be tolerated at room temperature. Moderate to good yields were generated.

Nickel-Catalyzed Cross-Coupling Reactions of Unreactive Phenolic Electrophiles via C-O Bond Activation

Nickel-catalyzed cross-coupling reactions of aryl esters, carbamates, carbonates, ethers and arenols are reviewed. Carbon-oxygen bonds in these phenol derivatives cannot be activated by palladium, a typical cross-coupling catalyst, but a low valent nickel species in conjunction with a strong σ-donor ligand is uniquely effective for achieving this. The review is organized primarily by substrate class and secondarily by coupling partners, encompassing organometallics, heteroatom nucleophiles, C-H bonds and many others. Although the reactions in this category are covered thoroughly, each reaction is described only briefly, so that it is possible to quickly overview the spectrum of nickel-catalyzed cross-coupling reactions of inert phenol derivatives. The robustness of inert phenol derivatives under typically used catalytic conditions as well as their utility as a directing group allow unique synthetic applications of these new C-O cross-coupling reactions, which is also included in cases where appropriate. Mechanistic aspects of C-O bond activation by nickel are also summarized, highlighting their diversity compared with the C-X bond activation involved in conventional cross-coupling processes.

Nickel-catalyzed synthesis of (E)-olefins from benzylic alcohol derivatives and arylacetonitriles via C–O activation

An efficient Ni-catalyzed synthesis of (E)-olefins using the readily available benzylic alcohol derivatives and arylacetonitriles is described. This transformation should proceed via a tandem process involving nickel-catalyzed cross coupling via C–O activation and subsequent stereoselective E2 elimination.

Nickel catalyzed reduction of arenols under mild conditions

The mild Ni-catalyzed reduction of arenols features a broad substrate scope, non-sensitivity to steric hindrance and no over-reduction of the aryl ring.

Efficient nickel-catalyzed phosphinylation of C–S bonds forming C–P bonds

The first nickel-catalyzed phosphinylation of C–S bonds forming C–P bonds is developed. The reaction can proceed readily with the simple Ni(cod)₂ at a loading down to 0.1 mol% at the 10 mmol scale. Various aryl sulfur compounds, i.e. sulfides, sulfoxides and sulfones all couple with P(O)–H compounds to produce the corresponding organophosphorus compounds, which provides an efficient new method for the construction of C–P bonds.

Cu-Catalyzed hydrophosphorylative ring opening of propargyl epoxides: highly selective access to 4-phosphoryl 2,3-allenols

A CuI-catalyzed cross-coupling of propargyl epoxides with P(O)H compounds to produce 4-phosphoryl 2,3-allenols with excellent selectivity under mild conditions is disclosed.

Nickel-catalysed P–C bond formation via P–H/C–CN cross coupling reactions

Nickel-catalysed P–H/C–CN cross coupling reactions take place efficiently under mild reaction conditions affording the corresponding sp²C–P bonds. This transformation provides a convenient method for the preparation of both arylphosphines and arylphosphine oxides from the readily available P–H compounds and arylnitriles.

The synthesis of heteroleptic phosphines

This perspective presents an overview of modern synthetic approaches to heteroleptic phosphines.