Borane–tetrahydrofuran is an

adduct In chemistry, an adduct (; alternatively, a contraction of "addition product") is a product of a direct addition of two or more distinct molecules, resulting in a single reaction product containing all atoms of all components. The resultant is ...

derived from

borane Borane is an inorganic compound with the chemical formula . Because it tends to dimerize or form adducts, borane is very rarely observed. It normally dimerizes to diborane in the absence of other chemicals. It can be observed directly as a c ...

and

tetrahydrofuran Tetrahydrofuran (THF), or oxolane, is an organic compound with the formula (CH2)4O. The compound is classified as heterocyclic compound, specifically a cyclic ether. It is a colorless, water- miscible organic liquid with low viscosity. It is ...

(THF). These solutions, which are colorless, are used for reductions and

hydroboration In organic chemistry, hydroboration refers to the addition of a hydrogen-boron bond to certain double and triple bonds involving carbon (, , , and ). This chemical reaction is useful in the organic synthesis of organic compounds. Hydroboration ...

, reactions that are useful in synthesis of organic compounds. A common alternative to BH₃•THF is borane–dimethylsulfide, which has a longer shelf life and effects similar transformations.Marek Zaidlewicz, Herbert C. Brown, Santhosh F. Neelamkavil, "Borane–Tetrahydrofuran" Encyclopedia of Reagents for Organic Synthesis, 2008 John Wiley & Sons.

Preparation and uses

The complex is commercially available but can also be generated by the dissolution of diborane in THF. Alternatively, it can be prepared by the oxidation of

sodium borohydride Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, is an inorganic compound with the formula (sometimes written as ). It is a white crystalline solid, usually encountered as an aqueous basic solution. Sodi ...

with

iodine Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a vi ...

in THF. The complex can reduce carboxylic acids to alcohols and is a common route for the reduction of

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...

s to

amino alcohols In organic chemistry, alkanolamines (amino alcohols) are organic compounds that contain both hydroxyl () and amino (, , and ) functional groups on an alkane backbone. Alkanolamine's bifunctionality and physicochemical characteristics lead to its u ...

(e.g.

valinol Valinol is an organic compound named after, and commonly produced from, the amino acid valine. The compound is chiral and is produced almost exclusively as the S‑isomer (also designated as the L‑isomer), due to the abundant supply of S-valine. ...

). It adds across alkenes to give organoboron compounds that are useful intermediates. The following organoboron reagents are prepared from borane-THF: 9-borabicyclo .3.1onane, Alpine borane,

diisopinocampheylborane Diisopinocampheylborane is an organoborane that is useful for asymmetric synthesis. This colourless solid is the precursor to a range of related reagents. The compound was reported in 1961 by Zweifel and Brown in a pioneering demonstration of asym ...

. It is also used as a source of borane (BH₃) for the formation of adducts.

Safety

The solution is highly sensitive to air, requiring the use of

air-free technique Air-free techniques refer to a range of manipulations in the chemistry laboratory for the handling of compounds that are air-sensitive. These techniques prevent the compounds from reacting with components of air, usually water and oxygen; less com ...

References

{{DEFAULTSORT:Borane-tetrahydrofuran Boranes Reagents for organic chemistry

Preparation and uses

Safety

See also

References