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Many selective reductions of carbonyl compounds can be effected by taking advantage of the unique reactivity profiles of metal alkoxylaluminium hydrides. For instance, lithium tri- tert -butoxy)aluminium hydride (LTBA) reduces aldehydes and ketones selectively in the presence of esters, with which it reacts extremely slowly.
Ternary metal hydrides have the formula A x MH n, where A + is an alkali or alkaline earth metal cation, e.g. K + and Mg 2+. A celebrated example is K 2 ReH 9, a salt containing two K + ions and the ReH 9 2− anion. Other homoleptic metal hydrides include the anions in Mg 2 FeH 6 and Mg 2 NiH 4.
Classical transition metal hydride feature a single bond between the hydrogen centre and the transition metal. Some transition metal hydrides are acidic, e.g., HCo(CO) 4 and H 2 Fe(CO) 4. The anions potassium nonahydridorhenate [ReH 9] 2− and [FeH 6] 4− are examples from the growing collection of known molecular homoleptic metal hydrides. [16]
In general, complex metal hydrides have the formula M x M' y H n, where M is an alkali metal cation or cation complex and M' is a metal or metalloid.Well known examples feature group 13 elements, especially boron and aluminium including sodium aluminium hydride, NaAlH 4), lithium aluminium hydride, LiAlH 4, and lithium borohydride, (LiBH 4).
β-Hydride elimination is a reaction in which a metal-alkyl centre is converted into the corresponding metal-hydride-alkene. [1] β-Hydride elimination can also occur for many alkoxide complexes as well. The main requirements are that the alkyl group possess a C-H bond β to the metal and that the metal be coordinatively unsaturated.
Reductions with hydrosilanes are methods used for hydrogenation and hydrogenolysis of organic compounds. The approach is a subset of ionic hydrogenation . In this particular method, the substrate is treated with a hydrosilane and auxiliary reagent, often a strong acid, resulting in formal transfer of hydride from silicon to carbon. [ 1 ]
The reduction of nitro compounds are chemical reactions of wide interest in organic chemistry. The conversion can be effected by many reagents. The nitro group was one of the first functional groups to be reduced. Alkyl and aryl nitro compounds behave differently. Most useful is the reduction of aryl nitro compounds.
While copper (I) hydride was the earliest known binary metal hydride (1800s), synthetic organic chemist’s interest in the reactivity of copper hydride complexes did not arise until nearly a century later; this interest came in the form of the now broadly utilized Stryker’s reagent (PPh3-modified CuH Hexamer) to affect hydrocuprations of unsaturated ketones – resulting in either 1,4 or 1 ...