Aluminum chloride alkyl halide reduction

Allyl halides, reduction reactions, 31 Aluminum chloride reagent/catalyst alkyl halide reduction, 30-31 secondary alkyl alcohol reduction, 14-15... 

Bromoadamantane and 1-bromoadamantane are reduced to adamantane in yields of 84% and 79%, respectively, when treated with triethylsilane and catalytic amounts of aluminum chloride.186 Similar treatment of benzhydryl chloride and exo-2-bromonorbomane gives the related hydrocarbons in yields of 100% and 96%, respectively.186 In contrast, 2-bromo-l-phenylpropane gives only a 43% yield of 1-phenylpropane the remainder consists of Friedel-Crafts alkylation products.186 Some alkyl halides resist reduction by this method, even when forcing conditions are employed. These include p-nitrobenzyl bromide, 3-bromopropanenitrile, and 5-bromopentanenitrile.186... 

Protodehalogenation.1 This hydride is the reagent of choice for hydrogenolysis of alkyl halides. Lithium aluminum hydride is somewhat less powerful, particularly for reduction of alkyl chlorides. 

Halides and tosylates. Trevoy and W. G. Brown found that lithium aluminum hydride reduces benzyl iodide and benzyl bromide in high yield at 35° in either diethyl ether or tetrahydrofurane. In tetrahydrofurane at 65°, benzyl chloride and 1 -bromodecane are reduced to toluene and to n-decane, both in 72% yield. Johnson, Blizzard, and Carhart found that lithium aluminum hydride reacts more sluggishly than in other reductions and presented experimental evidence that not all four hydrogen atoms possess adquate reactivity toward alkyl halides. Thus the reaction probably proceeds in at least two steps, the first of which is much more rapid than... 

Keduction of alkyl halides. Alkyl halides are reduced readily to hydrocarbons by organosilanes under catalysis with aluminum chloride. This hydrocarbon synthesis is limited to alkyl halides that are not rearranged by the catalyst. Primary, secondary, and tertiary halides are reduced. Reduction with triethyl-... 

The second pathway is represented by Eqs. (8)—(11). These reactions involve reduction of the Nin halide to a Ni° complex in a manner similar to the generation of Wilke s bare nickel (37, 38) which can form a C8 bis-77-alkyl nickel (17) in the presence of butadiene [Eq. (9)]. It is reasonable to assume that in the presence of excess alkyaluminum chloride, an exchange reaction [Eq. (10)] can take place between the Cl" on the aluminum and one of the chelating 7r-allyls to form a mono-77-allylic species 18. Complex 18 is functionally the same as 16 under the catalytic reaction condition and should be able to undergo additional reaction with a coordinated ethylene to begin a catalytic cycle similar to Scheme 4 of the Rh system. The result is the formation of a 1,4-diene derivative similar to 13 and the generation of a nickel hydride which then interacts with a butadiene to form the ever-important 7r-crotyl complex [Eq. (11)]. 

Primary and secondary alkyl bromides, iodides, and sulfonates can be reduced to the corresponding alkanes with LiBHEt3 (superhydride) or with lithium aluminum hydride (LiAlH4, other names lithium tetrahydridoaluminate or lithium alanate). If such a reaction occurs at a stereocenter, the reaction proceeds with substantial or often even complete stereoselectivity via backside attack by the hydride transfer reagent. The reduction of alkyl chlorides to alkanes is much easier with superhydride than with LiAlH4. The same is true for sterically hindered halides and sulfonates ... 

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