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Diborane(6), commonly known as diborane, is the chemical compound with the formula B 2 H 6.It is a highly toxic, colorless, and pyrophoric gas with a repulsively sweet odor. . Given its simple formula, borane is a fundamental boron compou
In general, if more than one alkene can be formed during dehalogenation by an elimination reaction, the more stable alkene is the major product. There are two types of elimination reactions, E1 and E2. An E2 reaction is a One step mechanism in which carbon-hydrogen and carbon-halogen bonds break to form a double bond. C=C Pi bond.
In an RCM reaction, the alkylidene undergoes an intramolecular [2+2] cycloaddition with the second reactive terminal alkene on the same molecule, rather than an intermolecular addition of a second molecule of starting material, a common competing side reaction which may lead to polymerization [26] Cycloelimination of the metallacyclobutane ...
Diborane reacts with alkenes to give alkylboranes, a process known as hydroboration: B 2 H 6 + 2 CH 2 =CHR → 2 BH 2 (CH 2 CH 2 R) B 2 H 6 + 4 CH 2 =CHR → 2 BH(CH 2 CH 2 R) 2 B 2 H 6 + 6 CH 2 =CHR → 2 B(CH 2 CH 2 R) 2. Alkyl and aryl boranes can also be produced by alkylation of chloroboranes and boronic esters.
Hydroboration of 1,2-disubstituted alkenes, such as a cis or trans olefin, produces generally a mixture of the two organoboranes of comparable amounts, even if the steric properties of the substituents are very different. For such 1,2-disubstituted olefins, regioselectivity can be observed only when one of the two substituents is a phenyl ring.
The metal-mediated processes include a carbonyl-olefination and an olefin–olefin metathesis event. There are two general mechanistic schemes to perform this overall transformation: one, reaction of a [M=CHR 1] reagent with an alkene to generate a new metal alkylidene, which then couples with a carbonyl group to form the desired substituted alkene and an inactive [M=O] species (type A); two ...
The reaction thus provides a more stereospecific and complementary regiochemical alternative to other hydration reactions such as acid-catalyzed addition and the oxymercuration–reduction process. The reaction was first reported by Herbert C. Brown in the late 1950s [2] and it was recognized in his receiving the Nobel Prize in Chemistry in 1979.
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.