
%0 Journal Article
%A Della, Ernest W. 
%A Janowski, Wit K. 
%T Competing Radical- and Anion-Mediated Pathways in the Reduction of Bridgehead Tosylates with Lithium Aluminium Hydride
%J Australian Journal of Chemistry
%D 1999/07/23
%V 52
%N 5
%P 367-372
%K 
%R https://doi.org/10.1071/CH98165
%U https://www.publish.csiro.au/paper/CH98165 
%X Reaction of norborn-1-yl tosylate with lithium aluminium hydride in boiling tetrahydrofuran affords a mixture of norbornan-1-ol accompanied by the ring-opened products 4-methylcyclohexanol and 3-ethylcyclopentanol as their cis/trans isomers, as well as p-thiocresol and p-tolyl disulfide. Evidence strongly suggests that the reaction is mediated by the norborn-1-yloxy radical rather than the norborn-1-yloxy anion. The process is initiated by very slow acyl oxygen fission of the norbornyl tosylate, followed by reduction of the derived p-toluenesulfinate ion to give the p-thiocresoxide anion. Transfer of an electron from the latter to the substrate and decomposition of the derived norborn-1-yl tosylate radical anion leads to the norborn-1-yloxy radical which, upon ring opening, generates the monocyclic alcohols via the corresponding ketones. It is noteworthy that, when norborn-1-yl mesylate is exposed to lithium aluminium hydride, it yields norbornan-1-ol exclusively. In the absence of an efficient electron-transfer agent, the mechanism of reaction of norborn-1-yl mesylate is suggested to involve acyl oxygen fission only. 
