Asymmetric Epoxidation of Enones Promoted by Dinuclear Magnesium Catalyst

Abstract

Asymmetric synthesis with cheaper and non-toxic alkaline earth metal catalysts is becoming an important and sustainable alternative to conventional catalytic methodologies mostly relying on precious metals. In spite of some sustainable methods for enantioselective epoxidation of enones, the development of a well-defined and efficient catalyst based on magnesium complexes for these reactions is still a challenging task. In this perspective, we present the application of chiral dinuclear magnesium complexes for asymmetric epoxidation of a broad range of electron-deficient enones. We demonstrate that the in situ generated magnesium-ProPhenol complex affords enantioenriched oxiranes in high yields and with excellent enantioselectivities (up to 99% ee). Our extensive study verifies the literature data in this area and provides a step forward to better understand the factors controlling the oxygenation process. Elaborated catalyst offers mild reaction conditions and a truly wide substrate scope.

Oxidation reactions of cyclopent-2-en-1-yl thiophene derivatives

“…The yield was 1.67 g. GCMS: compound (3) 5.68 min, m/z 150 -21.8%; compound (6a) 7.33 min, m/z 166 -35.29%; compound (6b) 7.65 min, m/z 166 -43.53%. Similarly, (Experiment I) with the ratio 2-Iodo-thiophene (7). Synthesised according to the method of H.Y.…”

“…Epoxides can interact with enzymes, which leads to modification of their activity (6) . They can act as inhibitors or activators of enzymatic reactions, which will affect various biochemical processes, including metabolism, and establish covalent bonds with DNA and RNA nucleotides, which can lead to modification of genetic material and significantly affect the processes of replication, transcription and translation of genetic information (7) . From a chemical standpoint, epoxides are typical electrophiles that are capable of establishing open-ring products with the participation of nucleophiles (8) .…”