The oxymercuration of conformationally biassed cyclohex-2-enols

Abstract

The oxymercuration–reduction of cis-5-t-butylcyclohex-2-enol (I) in 50% aqueous tetrahydrofuran proceeds with high stereoselectivity to give trans-3-hydroxy-cis-5-t-butylcyclohexanol (III). With trans-5-t-butylcyclohex-2-enol (II) the reaction is much less stereoselective and the major product is cis-3-hydroxy-trans-5-t-butylcyclohexanol (IV). Kinetic data for oxymercuration of these and related olefinic substrates have been obtained. The results are considered in terms of the possible directing influence of the hydroxy-group. It is concluded that this influence is predominantly of a polar (inductive) nature, and that a direct stabilising interaction between hydroxy and a cis-vicinal mercury atom is small or non-existent.