A phosphoramidite (RO)₂PNR₂ is a monoamide of a

phosphite The general structure of a phosphite ester showing the lone pairs on the P In organic chemistry, a phosphite ester or organophosphite usually refers to an organophosphorous compound with the formula P(OR)3. They can be considered as esters of a ...

diester. The key feature of phosphoramidites is their markedly high reactivity towards

nucleophile In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are ...

s catalyzed by weak acids ''e.c''., triethylammonium chloride or 1''H''-

tetrazole Tetrazoles are a class of synthetic organic heterocyclic compound, consisting of a 5-member ring of four nitrogen atoms and one carbon atom. The name tetrazole also refers to the parent compound with formula CH2N4, of which three isomers can be fo ...

. In these reactions, the incoming nucleophile replaces the NR₂ moiety.

Applications

Nucleoside phosphoramidites

Phosphoramidites derived from protected nucleosides are referred to as

nucleoside phosphoramidite Nucleoside phosphoramidites are derivatives of natural or synthetic nucleosides. They are used to synthesize oligonucleotides, relatively short fragments of nucleic acid and their analogs. Nucleoside phosphoramidites were first introduced in 19 ...

s and are widely used in chemical synthesis of DNA, RNA, and other nucleic acids and their analogs.

As ligands

Certain phosphoramidites are also used as

monodentate In coordination chemistry, denticity () refers to the number of donor groups in a given ligand that bind to the central metal atom in a coordination complex. In many cases, only one atom in the ligand binds to the metal, so the denticity equals ...

chiral ligand Enantioselective synthesis, also called asymmetric synthesis, is a form of chemical synthesis. It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of chirality are formed in a substrate molecu ...

s in asymmetric synthesis. A large group of such ligands is derived from the chiral diol BINOL and can be synthesised by reaction of BINOL with

phosphorus trichloride Phosphorus trichloride is an inorganic compound with the chemical formula PCl3. A colorless liquid when pure, it is an important industrial chemical, being used for the manufacture of phosphites and other organophosphorus compounds. It is toxi ...

to the chlorophosphite and then reaction with simple secondary

amine In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituen ...

s. This type of ligand was first used in 1996 in an asymmetric copper-catalysed addition of dialkylzincs to enones.

References

{{organophosphorus Functional groups

Applications

Nucleoside phosphoramidites

As ligands

See also

References