Phosphines are obtained by reacting phosphorus trichloride with organometallic reagents. Thus, phosphorus trichloride reacts with phenylmagnesium bromide to form triphenylphosphine.

phosphines 01

This reaction is well controlled and allows only two groups to be introduced.

An important application of tertiary phosphines is the stabilization of coordination complexes, they are very common ligands in this type of compounds.
Tertiary phosphines react with alkyl halides to form phosphonium salts, which can be used in the preparation of phosphorus ylides.
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phosphonium salt
phosphorous ylide
Phosphorus ylides react with carbonyls to form alkenes, this is the famous Wittig reaction.
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