Preparation Of D-borneol By Asymmetric Reduction Of Camphor

Recently, asymmetric synthesis of Alcohol from ketone compounds has been developed rapidly and some progress has been made. Alkali metals could be dissolved in solvents and form various systems to reduce many functional groups. Alkali metals become important reducers in organic reactions due to ease control of reaction temperature, moderation of reaction conditions and high yields.In this paper, The asymmetric reduction of camphor into D-borneol was carried out in Alkali metal/alcohol and alkali metal/Tetrahydrofuran (THF) system by taking advantage of the molecular thermodynamical stability of midway products of camphor reduction.The experimentation results indicated that the main product was D-borneol and the byproduct was isoborneol. The highlight of this dissertation is as follows:1) Reaction mechanism of reduction of camphor by alkali metal/alcohol and alkali metal/THF was discussed;The conditions and factors influencing reduction of camphor into D-borneol by two alkali metal (sodium and Potassium) and two solvents (ethanol and THF) compages was particular investigated, and the optimal reduction condition of each compage system was proposed.2) The experimental results indicated that the ratio of D-borneol of alkali metal/alcohol reduction are more than 80%,but The ratio of alkali metal/THF reductions are small.In order to improve the ratio of D-borneol,the bromized alkali metal salt or other proton donor was added to improve the ratio of D-borneol of the camphor reduction offsprings,and the ratio of D-borneol obviously improved.3) Because camphor could not be reduced completely in the first reduction,there exists lots of camphor in the resulting product.The second...