Synthesis and asymmetric transformations of diols by enzyme- and ruthenium catalysis

Sammanfattning: The major part of this thesis describes the synthesis of aliphatic secondary diols and the development of lipase- and ruthenium-catalyzed asymmetric transformations of these diols.Several acyclic 1,4-diols and 1,5-diols were synthesized, and by combining a lipase-catalyzed asymmetric transformation with a ruthenium-catalyzed epimerization, enantiomerically- and diastereomerically enriched diacetates were obtained. The scope and limitations of the system were also investigated, and some problems were encountered with electron-deficient diols. The diacetate products were further transformed into natural product heterocycles and chiral ligands.A thorough study of the enzyme-catalyzed asymmetric transformation of 1,3-cyclohexanediol was also performed. It was found that there was a difference in the enzyme selectivity for the cis- and trans- diols, respectively, and while poor selectivity was observed for the trans-diol, cis-1,3-cyclohexanediol could be efficiently desymmetrized. By adding different epimerization catalysts, both cis- and trans-1,3-cyclohexanediol could be obtained in high enantio- and diastereoselectivities. The use of hydrogen transfer for the reduction of cyclic 1,3-diketones was also demonstrated, and the reactions could in many cases be carried out in a microwave oven.