Mastering Chirality: Unlocking Bioactive Natural Products with Oxazaborolidines and Oxazaborolidinones

Catalytic asymmetric synthesis has appeared as the preferred method for producing enantiomerically pure compounds, marking significant advancements in recent years. In biological processes, asymmetric catalysis governs the synthesis of chiral compounds, facilitated through the chirality transfer following reactant binding at enzyme active sites. A revolutionary milestone in this area was the discovery of oxazaborolidine chiral catalysts by Corey, Bakshi, and Shibata (CBS catalysts), empowering the enantioselective reduction of achiral ketones. This discovery has had profound implications across industry and academia, establishing oxazaborolidines as pivotal tools for achieving chirality in chemical systems. The application of oxazaborolidines and their derivatives have been extensively explored for enantioselective reductions of various functional groups. While previous review articles focused on specialized functional groups, this review provides an overview (last fifteen years) of practical advancements in the use of borane-oxazaborolidine catalysts for the enantioselective reduction of challenging functional groups such as ketones, ketimines, and oximes. These advancements have facilitated the synthesis of various building blocks for natural products. We also highlighted the potential of oxazaborolidinones as it was remains largely underutilized, presenting an exciting opportunity for future investigations.