The sodium borohydride reduction of organic halides and related derivatives in aprotic solvents

Sodium borohydride reduces alkyl halides and their related tosylate derivatives in the order primary > secondary > tertiary, while the relative order of leaving-group ability is Ts⁻ ≥ I⁻ > Br⁻ > > Cl⁻. The yields obtained ranged from 90-100% for most simple, primary and secondary iodides, bromides, and tosylates, to 1-2% for the tertiary compounds. As in the case of the more reactive lithium aluminum hydride, the. reduction is believed to occur by an S_N2 displacement on carbon. The reduction of a series of para-substituted benzyl chlorides revealed that the electronic effects of groups ranging from p-methoxy to p-nitro had a rather small effect on the rate of reduction. Aryl halides arc reduced by sodium borohydride in yields dependent upon the particular halogen involved, the presence of other ortho and para electron-withdrawing substituents, and the reaction temperature, among other factors. The same relative order of dehalogenation displayed by the alkyl halides was found. Polyhalomethanes such as carbon tetrachloride react with sodium borohydride to give the monohydro and dihydro compounds as the major products, the former predominating. The exact mechanism of the reduction is as yet undetermined, as water apparently catalyzes the reaction in some unknown manner.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Department dc:contributor.department

Chemistry

Grantor dc:publisher

Virginia Polytechnic Institute

Year dc:date.issued

1968

Author dc:creator

• Vanderslice, Charles Warren

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10919/88554

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/88554