CPhos is a

phosphine ligand A metal-phosphine complex is a In coordination complex containing one or more phosphine ligands. Almost always, the phosphine is an organophosphine of the type R3P (R = alkyl, aryl). Metal phosphine complexes are useful in homogeneous catalysis. P ...

derived from

biphenyl Biphenyl (also known as diphenyl, phenylbenzene, 1,1′-biphenyl, lemonene or BP) is an organic compound that forms colorless crystals. Particularly in older literature, compounds containing the functional group consisting of biphenyl less one ...

. It is a white solid that is soluble in organic solvents. Its

palladium Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself na ...

complexes exhibit high activity for Negishi coupling reactions involving aryl bromides, chlorides and triflates. CPhos mediated reactions performed with secondary (sp³) alkylzinc halides often give excellent yields, with low conversion to the frequently encountered primary substituted

by-product A by-product or byproduct is a secondary product derived from a production process, manufacturing process or chemical reaction; it is not the primary product or service being produced. A by-product can be useful and marketable or it can be consid ...

Utility in Negishi Coupling

A simplified

scheme A scheme is a systematic plan for the implementation of a certain idea. Scheme or schemer may refer to: Arts and entertainment * ''The Scheme'' (TV series), a BBC Scotland documentary series * The Scheme (band), an English pop band * ''The Schem ...

showing the reaction course of isopropylzinc bromide with an aryl halide is shown below. Processes leading to byproduct formation are highlighted in red. Oxidative addition (1) of the aryl halide to the palladium-

ligand In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electr ...

complex followed by

transmetalation Transmetalation (alt. spelling: transmetallation) is a type of organometallic reaction that involves the transfer of ligands from one metal to another. It has the general form: :M1–R + M2–R′ → M1–R′ + M2–R where R and R′ can be, but ...

(2) gives intermediate B which can undergo reductive elimination (3) to afford the desired isopropyl arene C. However, intermediate B can also undergo

β-hydride elimination β-Hydride elimination is a reaction in which an alkyl group bonded to a metal centre is converted into the corresponding metal-bonded hydride and an alkene. The alkyl must have hydrogens on the β-carbon. For instance butyl groups can undergo th ...

(4) to afford D, which can either reductively eliminate (3’) to afford de-halogenated product G, or undergo

insertion Insertion may refer to: *Insertion (anatomy), the point of a tendon or ligament onto the skeleton or other part of the body *Insertion (genetics), the addition of DNA into a genetic sequence *Insertion, several meanings in medicine, see ICD-10-PCS ...

(5) leading to the formation of E. Once formed, E may also undergo reductive elimination (3’’) to afford the ''n''-propyl by-product F. CPhos minimises the conversion to undesired products F & G by increasing the rate of the reductive elimination of B, relative to the rate of

References

{{Reflist

External links

CPhos at Sigma Aldrich

CPhos Pd G2 (precatalyst) at Sigma Aldrich

CPhos Pd G3 (precatalyst) at Sigma Aldrich
Tertiary phosphines

Utility in Negishi Coupling

See also

References

External links