Search results
Results From The WOW.Com Content Network
In the hydroboration reaction, diborane also reacts readily with alkenes to form trialkylboranes. This reaction pattern is rather general and the resulting alkyl borates can be readily derivatized, e.g. to alcohols. Although early work on hydroboration relied on diborane, it has been replaced by borane dimethylsulfide, which is more safely handled.
Disiamylborane (bis(1,2-dimethylpropyl)borane) is an organoborane with the formula [((CH 3) 2 CHCH(CH 3)) 2 BH] 2 (abbreviation: Sia 2 BH). It is a colorless waxy solid that is used in organic synthesis for hydroboration–oxidation reactions. Like most dialkyl boron hydrides, it has a dimeric structure with bridging hydrides.
This chemical reaction is useful in the organic synthesis of organic compounds. [1] Hydroboration produces organoborane compounds that react with a variety of reagents to produce useful compounds, such as alcohols, amines, or alkyl halides. The most widely known reaction of the organoboranes is oxidation to produce alcohols from alkenes.
Hydroboration–oxidation reaction is a two-step hydration reaction that converts an alkene into an alcohol. [1] The process results in the syn addition of a hydrogen and a hydroxyl group where the double bond had been. Hydroboration–oxidation is an anti-Markovnikov reaction, with
Borane adducts are widely used in organic synthesis for hydroboration, where BH 3 adds across the C=C bond in alkenes to give trialkylboranes: [13] (THF)BH 3 + 3 CH 2 =CHR → B(CH 2 CH 2 R) 3 + THF. This reaction is regioselective. [14] Other borane derivatives can be used to give even higher regioselectivity. [15]
In addition to terminal alkenes, tri- and tetrasubstituted alkenes have been used in RCM reactions to afford substituted cyclic olefin products. [32] Ring-closing metathesis has also been used to cyclize rings containing an alkyne to produce a new terminal alkene , or even undergo a second cyclization to form bicycles.
It adds across alkenes to give organoboron compounds that are useful intermediates. [4] The following organoboron reagents are prepared from borane-THF: 9-borabicyclo[3.3.1]nonane, Alpine borane, diisopinocampheylborane. It is also used as a source of borane (BH 3) for the formation of adducts. [5]
Heating may be used to encourage oxidation, although the reaction temperature should never exceed 50 °C, to avoid decomposition of the dioxirane [1] Alkenes bound to both electron-withdrawing and -donating groups tend to behave like the former, requiring long oxidation times and occasionally some heating.