Complex reducing agents alkyl halides

The general reactions of the compounds are much as expected. They react with strong reducing agents to give ammonia and amines, with complete destruction of the cora-plexes. " The halides are labile and can be substituted. " The compounds react with acids to form alkylhydrazido complexes, " and with alkyl halides to form dialkylhydrazido(2 —) complexes, in reactions which are typical Sn2 reactions, "" though electrophilic attack (viz. by Me ") is also a possibility. ... 

The at complex from DIB AH and butyllithium is a selective reducing agent.16 It is used tor the 1,2-reduction of acyclic and cyclic enones. Esters and lactones are reduced at room temperature to alcohols, and at -78 C to alcohols and aldehydes. Acid chlorides are rapidly reduced with excess reagent at -78 C to alcohols, but a mixture of alcohols, aldehydes, and acid chlorides results from use of an equimolar amount of reagent at -78 C. Acid anhydrides are reduced at -78 C to alcohols and carboxylic acids. Carboxylic acids and both primary and secondary amides are inert at room temperature, whereas tertiary amides (as in the present case) are reduced between 0 C and room temperature to aldehydes. The at complex rapidly reduces primary alkyl, benzylic, and allylic bromides, while tertiary alkyl and aryl halides are inert. Epoxides are reduced exclusively to the more highly substituted alcohols. Disulfides lead to thiols, but both sulfoxides and sulfones are inert. Moreover, this at complex from DIBAH and butyllithium is able to reduce ketones selectively in the presence of esters. 

Lithium aluminum hydride (LAH) reacts with pyridines and their analogs in aprotic solvents to give dihydro- and tetrahydro-pyridines. In the absence of proton sources dihydropyridines normally predominate, solutions of pyridine and LAH form lithium complexes (32 Scheme 7), which likely consist of both 1,2- and 1,4-dihydropyridlnes. This intermediate has been used as a reducing agent for ketones, and reaction with alkyl halides generates 3-substituted pyridines (33) in good yield. 

Lithium aluminum hydride (LAH) reductions are carried out in aprotic solvents and give rise to the dihydro- and tetrahydropyridine derivatives. LAH reacts with both pyridines and pyridinium salts. It has been known for some time that aged ( 24 h) pyridine and LAH solutions form complexes of lithium tetrakis(A -dihydropyridinyl)aluminate (40, LDPA), - which is believed to consist of a mixture of the 1,2- and 1,4-dihydropyridines (by NMR). Indeed, LDPA itself has been used as a selective reducing agent for ketones and affords 3-substituted pyridines (41) on reaction with alkyl halides. 2,5-Dihydropyridines have been identified as intermediates in similar reactions. Kuthan and co-workers have shown that for 3,5-dicyan-... 

Anionic dinitrogen complexes of MeP and W of the type trans - [M(N2)X(Ph2PCH2CH2PPh2)2] (X = N3, CN, SCN) are moderately strong reducing agents with oxidation potentials in the vicinity of -1 V versus SCE. They undergo an outer sphere electron - transfer with alkyl halides to produce M dinitrogen 17 - electron intermediates and alkyl radicals. Scheme E. The fates of both... 

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