Copper I hydride

Both the acid and its salts are powerful reducing agents. They reduce, for example, halogens to halides, and heavy metal cations to the metal. Copper(H) ion is reduced further to give copper(I) hydride, a red-brown precipitate ... 

Regioselective coniugale reduction and reductive silylation of a,p-unsaturated ketones, esters, and aldehydes using a stable copper (I) hydride cluster (Ph3P)CuH 6... 

Three new methods for the conversion of alkynes to (Z)-alkenes were reported, although Lindlar semi-hydrogenation still remains as the most convenient method. Copper (I) hydride reagent could reduce alkynes to (Z)-alkenes as shown in Scheme 3 [12]. Yoon employed nickel boride prepared on borohy-dride exchange resin for selective hydrogenation of alkynes to (Z)-alkenes (Scheme 4) [13]. 

Conjugate reduction.1 This stable copper(I) hydride cluster can effect conjugate hydride addition to a,p-unsaturated carbonyl compounds, with apparent utilization of all six hydride equivalents per cluster. No 1,2-reduction of carbonyl groups or reduction of isolated double bonds is observed. Undesirable side reactions such as aldol condensation can be suppressed by addition of water. Reactions in the presence of chlorotrimethylsilane result in silyl enol ethers. The reduction is stereoselective, resulting in hydride delivery to the less-hindered face of the substrate. 

Intermediates such as 224 resulting from the nudeophilic addition of C,H-acidic compounds to allenyl ketones such as 222 do not only yield simple addition products such as 225 by proton transfer (Scheme 7.34) [259]. If the C,H-acidic compound contains at least one carbonyl group, a ring dosure is also possible to give pyran derivatives such as 226. The reaction of a similar allenyl ketone with dimethyl mal-onate, methyl acetoacetate or methyl cyanoacetate leads to a-pyrones by an analogous route however, the yields are low (20-32%) [260], The formation of oxaphos-pholenes 229 from ketones 227 and trivalent phosphorus compounds 228 can similarly be explained by nucleophilic attack at the central carbon atom of the allene followed by a second attack of the oxygen atom of the ketone at the phosphorus atom [261, 262], Treatment of the allenic ester 230 with copper(I) chloride and tributyltin hydride in N-methylpyrrolidone (NMP) affords the cephalosporin derivative 232 [263], The authors postulated a Michael addition of copper(I) hydride to the electron-... 

There are many examples of borohydride compounds of these metals, e.g., Cu, Ag, Zn and Cd-BH as neutral and anionic complexes in which the mode of bonding of BH is dependent on the coordination number of the metaP. Higher borane anions also combine with Cu and Ag, yielding both neutral and anionic complexes. Although no borohydrides of Au are isolated, treatment of Au-halide complexes with, e.g., NaBH, is a standard method for the preparation of Au-cluster compounds Copper(I) hydride, first reported in 1844, has the ZnS structure [d(Cn-H) = 0.173 nm (1.73 A) d(Cu-Cu) = 0.289 nm (2.89 A)] and decomposes to the elements when heated. At >100°C the decomposition is explosive. 

The stable, well-characterized copper(I) hydride cluster [(PPh3)CuH]6 is a useful reagent for conjugate reduction of a,p-unsaturated carbonyl compounds. o This hydride donor is chemically compatible with chlorotrimethylsilane, allowing formation of silyl enol ethers via a reductive silation process (Scheme 53). 

The blood-red solution formed yields a bright red, crystalline solid when more ether is added. This is stable below 50° and decomposes rapidly above 100°. It is a copper(I) hydride, CuHq stoichiometrically deficient in hydrogen, and does not resemble the saline hydrides, having a low heat of formation (—AH =5.1 kcal/mole). 

The complex is obtained from tri-n-butylphosphine and copper(I) hydride, prepared by reduction of copper(I) bromide with diisobutylaluminum hydride at —50°. The complex is a useful reducing agent it reduces iodobenzene to benzene (80% yield) and benzoyl chloride to benzaldehyde (50% yield). In addition the complex reduces primary, secondary, and tertiary alkyl-, vinyl-, and arylcopper(l) compounds to the corresponding hydrocarbons in high yields, under mild conditions and with no rearrangements.1... 

Copper(I) hydride is obtained by reduction of Cu(II) salts with H3PO2 and crystallizes with the wurtzite structure. It decomposes when treated with acids, liberating H2. 

Copper(I) hydride complexes. Stabilization of CuH with various phosphines enables the use of such complexes to reduce carbonyl groups (in the presence of a double bond). ... 

Copper(I)hydride [13517-00-5] CU2H2 No toxic effect reported The dry solid ignites in air ignites with halogens reacts violently with oxidizers... 

Copper sulphate solution no precipitate in the cold, but on warming red copper(I) hydride is precipitated. 

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