Rearrangements lithium aluminum hydride

Among ring-fused systems, the 3-(o-aminoaryl)benzisoxazole (506) underwent rearrangement on refluxing in THF with sodium hydride or lithium aluminum hydride. In this case the 3-(o-hydroxyphenyl)benzimidazole (506a) was obtained. 

An alternate method of producing the 21-hydroxy-20-ketone consists in lithium aluminum hydride reduction of the dimethyl acetal, hydrolysis to the 20-hydroxy-21-aldehyde and rearrangement, preferably via the bisulfite addition product... 

Kuzuhara and his coworkers synthesized (+)-205 by hydroxylation of the alkene 304, which was prepared from the chiral azidocyclohexene derivative (303) derived from D-glucose, in which a novel rearrangement of the C - C double bond accompanying reduction of the azido group with lithium aluminum hydride was observed. 

TT-ALLYLNICKEL HALIDES METHALLYLBENZENE, 52, 115 Rearrangement of epoxides to allylic alcohols, 53, 17 Reduction, by controlled-po-tential electrolysis, 52, 22 by lithium aluminum hydride of exo-3,4-dichlorobicyclo [3.2.l]oct-2-ene to 3-chlorobicyclo[3.2.l]oct-2-ene, 51, 61... 

Many hydroxy compounds would not survive such harsh treatment therefore other methods must be used. Some alcohols were hydrogenolyzed with chloroalanes generated in situ from lithium aluminum hydride and aluminum chloride, but the reaction gave alkenes as by-products [605], Tertiary alcohols were converted to hydrocarbon on treatment at room temperature with triethyl- or triphenylsilane and trifluoroacetic acid in methylene chloride (yields 41-92%). Rearrangements due to carbonium ion formation occur [343]. 

Byproducts of this rearrangement are cyclobutenes, cyclopropane derivatives and allenic alcohols. The ratio of these products depends on the substitution of the substrate and on the reaction conditions. For example, 3-methyl-5-tosyloxypenta-l,2-diene (3) gives 75% of 1-methyl-2-methylenecyclobutanol (4) upon hydrolysis with water and calcium carbonate at 100 °C, while acetolysis with acetic acid/sodium acetate at 80 °C, and subsequent treatment with lithium aluminum hydride, provides only 37% of the cyclobutanol.12... 

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