STUDIES ON ENANTIOSELECTIVE DESYMMETRIZING ALKYNE HYDROSILYLATION

Abstract

This research focuses on the design and synthesis of enantioselective desymmetrizing α-hydrosilylation of propargyl alcohols to provide α-hydroxy (E)-vinylsilanes. Transition metal-catalyzed, regio-and stereoselective intramolecular hydrosilylation of propargylic alcohols with an easily removable acetal directing group has been studied. This project thus far screened 35 chiral ligands with rhodium (I) to achieve enantioselective alkyne hydrosilylation. This strategy consists of sequential hydrosilylation of bis-propargyl formate with iridium catalyst and intramolecular alkyne hydrosilylation with chiral rhodium catalyst. To this end, a variety of chiral phosphine ligands has been tested, yet an enantiomeric excess of the α-hydroxy (E)-vinylsilanes has not been fruitful thus far, which was determined by chiral HPLC analysis. However, the result showed that the bulkier chiral ligands generally gave better enantioselectivity. In future, further ligand screening as well as structural modification of hydrosilane will be performed to achieve the enantioselective intramolecular α-hydrosilylation of propargyl alcohols.