Stereoselective synthesis of dihydropyran derivatives by ring closing metathesis reactions

The aim of this thesis is to synthesize optically active heteroaryl-substituted dihydropyran derivatives from benzofuran and benzothiophene substituted homoallyl alcohols. In the first part of the study, benzofuran and benzothiophene-substituted homoallyl alcohol derivatives were synthesized as racemic mixtures. The homoallyl alcohols obtained were then enantiomerically purified by enzymatic resolution with various lipase enzymes. Optically active homoallylic alcohols have been converted into various dien and enyne derivatives by O-allylation and O-propargylation methods. Finally, these resulting derivatives were converted to the new chiral heteroaryl-substituted dihydropyran structures by ring closing metathesis reaction. The 1st and 2nd generation ruthenium-based Grubbs catalysts were used in ring closing metathesis reactions. These chiral dihydropyran derivatives are not present in the literature and they have the potential of showing various biological activities.