A Study of the Lithium in Ammonia Reduction of 3-Ethoxy cyclohexenone

The composition of the product mixture from the reduction of 3-ethoxycyclohexenone (1) by lithium in ammonia under a variety of conditions has been determined. By appropriate choice of conditions, the predominant product can be made any of four compounds: cyclohexanone (2), cyclohexanol (3), 3-ethoxycyclohexanone (4), or cis-3-ethoxycyclohexanol (5). At -78°, products formed via elimination of ethoxide from enolate anion 9, viz., 2 and 3, are not observed. At -33° this elimination has t_1/2, of ca. 7 min. Use at either temperature of absolute ethanol as a quenching reagent rather than ammonium chloride favors formation of the hydroxylic products 3 and 5.