Reactions with hydride derivatives

Since group 4 derived species are of particular interest as catalysts for olefin polymerization and epoxidation reactions, the thermal stability of surface metal-alkyl species, as weU as their reactivity towards water, alcohols and water, deserve some attention. On the other hand, mono(siloxy) metaUiydrocarbyl species can be converted into bis- or tris(siloxy)metal hydrides by reaction with hydrogen [16, 41, 46-48]. Such species are less susceptible to leaching and can be used as pre-catalysts for the hydrogenolysis of C-C bonds, alkane metathesis and, eventually, for epoxidation and other reactions. 

Hydride transfer reactions from NADH analogues to high-valent metal-oxo species provide excellent opportunity to clarify such a mechanistic difference by comparing the hydride transfer reactions with those with /)-benzoquinone derivatives, which have been discussed in the previous section. A series of NADH analogues, 10-methyl-9,10-dihydroacridine (AcrH2) and its 9-subsituted derivatives (AcrHR R =... 

Amides react with LiAlH4 differently than do other carbonyl derivatives. Reaction with LiAlH4 gives an intermediate iminium salt, which is further reduced to an amine as the final product. The net result of this two-step process is complete removal of oxygen from the molecule, illustrated by the reduction of amide 28, which gave amine 29 in 85% yield from Quirion s asymmetric synthesis of 1,4-disubstituted tetrahydroiso-quinolines.36 The reaction proceeds by initial transfer of hydride to the amide, forming a complex such as... 

Alkali met hydrides, superactive -, reactions with - 43, 34 Alkali metal selenides -, in s/tu-preparation 43, 529 Alkene oxides s. Oxido compds. Alkenes s. Ethylene derivs. 

Chemical properties of the batrachotoxin fraction were assessed on a microscale. In retrospect it appears that most reactions resulted in loss of the pyrrole entity and hence a product which did not afford a positive Ehrlich reaction. These chemical reactions included catalytic hydrogenation with palladium on charcoal, reduction with lithium aluminium hydride, treatment with acidic methanol, oxidation with manganese dioxide, treatment with acid, reaction with 2,4-dinitrophenylhydrazine, and exhaustive methylation with methyl iodide. An Ehrlich-positive methiodide could be obtained under milder conditions with methyl iodide. Acetylation of the batrachotoxin fraction with acetic anhydride and pyridine afforded two Ehrlich-positive 0-acetyl derivatives. Reaction with methoxyamine afforded an Ehrlich-positive 0-methyloxime. Reduction with sodium borohydride afforded an Ehrlich-positive dihydro-derivative. This product apparently isomerizes to other dihydro-compounds (257). Autoxidation, a serious problem during isolation of batrachotoxin, led to Ehrlich-negative products. 

Fig. 3. Synthesis of fluoxetine (31). 3-ChIoro-I-phenyl-I-propanol reacts with sodium iodide to afford the corresponding iodo derivative, followed by reaction with methylamine, to form 3-(methyl amin o)-1-phenyl-1-propan 0I. To the alkoxide of this product, generated using sodium hydride, 4-fluorobenzotrifluoride is added to yield after work-up the free base of the racemic fluoxetine (31), thence transformed to the hydrochloride (51)...

Similarly, the position of the acyl group in derivatives formed by the reaction with acetic hydride or benzoyl chloride and the position of the carboxymethyl group in the derivative formed by the reaction with chloracetic acid are not established. ... 

Tire 2-dimethylamino derivatives 147 were prepared by a three-step reaction pathway that comprised (a) methylation of the 2-acetamido derivative 144 with methyl iodide and sodium hydride to 145, (b) mild acid-catalyzed N-deacetylation of 145 to 146, and (c) further methylation of 146 to the 2-dimethylamino compound 147 (90JMC1230) (Scheme 57). 

Some alicyclic 1,2-diamine derivatives have recently been shown to have interesting CNS properties. For example, eclanamine (34) is an antidepressant with a rapid onset of action. The reasons for its potency are not as yet clear but pharmacologists note that the drug desensitizes adrenergic alpha-2 receptors and antagonizes the actions of clonidine. The synthesis of eclanamine starts with attack of cyclopentene oxide (30) by dimethylamine (to give 31). This product is converted to the mesylate by reaction with sodium hydride followed by mesyl chloride. Attack of... 

The reaction of the coordinatively unsaturated ruthenium amidinates with [Cp RuCl]4 tetramer or [CpRufMeCNlsJPFg provides access to novel amidinate-bridged dinuclear ruthenium complexes (Scheme 146), which in turn can be transformed into cationic complexes or hydride derivatives. In these complexes, a bridging amidinate ligand perpendicular to the metal-metal axis effectively stabilizes the highly reactive cationic diruthenium species. 

Corey and Chaykovsky had discovered that dimethyl sulfoxide is converted to methyl-sulfmyl carbanion upon treatment with sodium hydride " and that this conjugate base of DMSO reacts with various electrophiles This finding has opened up various reactions with a-sulfinyl carbanions derived from sulfoxides, since the sulfinyl function can be removed either by thermolysis or by subjecting the compound to reductive desulfurization. Thus a-sulfinyl carbanions have become versatile synthetically useful reagents. 

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