Selective Cathodic Birch Reductions

Article abstract of DOI:10.1021/jo00205a003

The electroreduction of some difficult to reduce substrates was investigated by using aqueous tetrahydrofuran, tetrabutylammonium (TBA⁺) electrolyte, and mercury cathodes.The reduction products formed in high yields and the current efficiencies were good.Benzene, anisole, 1,2,3,4-tetrahydro-6-methoxynaphthalene and β-estradiol 3-methyl ether reactions were carried out with constant current at room temperature and were found to be more selective than the corresponding alkali metal-ammonia reductions.Selective reduction of the carbonyl function of estrone methyl ether was achieved while the aromatic ring remained intact.The aqueous THF medium did not affect base-sensitive molecules and a reduction product from 17-α-ethynylestradiol 3-methyl ether could be obtained without loss of the ethynyl group.Most of the compounds studied did not exhibit polarographic waves.A reduction product of TBA⁺ was observed by cyclic voltammetry and it is proposed that TBA "amalgam" may participate as a mediator in the reduction of the organic substrates.