Highly diastereoselective transfer hydrogenation of 4-t-butylcyclohexanone in the presence of magnesium oxide

Abstract

The first report is described on the activity, selectivity and diastereoselectivity of magnesium oxide as a catalyst in the liquid and vapor phase modes (LP and VP) of catalytic transfer hydrogenation of 4-t-butylcyclohexanone (t-BuONE) using secondary alcohols as hydrogen donors. An exceptionally high diastereoselectivity ((98%) to trans- 4-t-butylcyclohexanol (trans-t-BuOL) in the LP mode of reaction, with almost all hydrogen donors used with MgO, has been observed. This is ascribed to the predominance of the axial attack on the ketone molecule and the reaction irreversibility.