As an essential shift metal catalyst,
Pd(PPh3)4 can be used to militarize different responses such as coupling, oxidation, reduction, removal, reformation, and isomerization. Its catalytic effectiveness is really high, and also it can militarize numerous responses that are tough to take place under the action of similar catalysts.
Catalytic carbon-carbon bond development
As an important catalyst, Pd(PPh3)4 is often used to catalyze the coupling reaction (Cross-Coupling Reaction) and is an important method for constructing carbon-carbon bonds, which is characterized by mild catalytic conditions. For example, under the combined action of Pd(PPh3)4 and Ag2O, phenylboronic acid was directly reacted with aromatic halogenated hydrocarbons to generate biphenyls in 90% yield (Equation 1). In addition to phenylboronic acid and halides, magnesium reagents, zinc reagents, tin reagents, silicon compounds, etc. can be used as substrates for the coupling reaction.
Under the catalysis of Pd(PPh3)4, halogenated aromatic hydrocarbons, etc. can directly react with olefin derivatives to form styrene derivatives (the reaction type is Heck reaction) (Equation 2).
Pd(PPh3)4 can also catalyze the coupling of alkyne compounds and halides (Sonogashira reaction). During the reaction, alkyne hydrogen and halogen element form hydrogen halide (or neutralize with alkali) and leave, and the product is alkyne. Derivatives (Formula 3).
At the same time, under the catalysis of Pd(PPh3)4, the C-H bond on the aromatic ring can be activated, and then it can react with halogenated compounds, tin compounds, etc. to remove a molecule of hydrogen halide or stannane to form a C-C bond (Formula 4 ).
In addition, since Pd(PPh3)4 can catalyze the formation of various C-C bonds, it is possible to construct reactions catalyzed by multiple sites at the same time, such as intermolecular cyclization reactions (Eq. 5).