s Titanium Catalyzed Enantioselective Oxidation of Thioethers with Hydrogen Peroxide

Catalytic asymmetric oxidation of prochiral sulfides has been a challenging goal for years, which reflects the importance of sulfinyl group as a chiral controller in many organic transformations, as well as the existence of natural and synthetic biologically active products that need a sulfinyl group with a defined stereoconfiguration. 30 years ago, owing to the milestone discoveries of Kagan and Modena, titanium-dialkyltartrate/alkyl hydroperoxide catalyst systems emerged as the protagonists in this area. In the last decade, various types of novel titanium based catalyst systems were developed, exploiting ‘green’ hydrogen peroxide as the terminal oxidant. This mini-review is aimed at discussing recent advances in enantioselective sulfoxidations with H2O2 in the presence of new generation chiral titanium catalysts, demonstrating high reactivity, efficiency, and enantioselectivity, which are likely to contribute to preparative syntheses of biologically active sulfoxides in near future. Peculiarities of their behavior and mechanisms of their catalytic action are discussed. Their viability is analyzed from the industrial and green chemistry perspectives.