Determination of the Absolute Configuration of Secondary Alcohols in a Compound Mixture via the Application of Competing Enantioselective Acylation Coupled with LC/MS Analysis

The determination of natural product stereochemistry plays a significant role in drug discovery and development. Understanding the stereochemistry of natural products is essential for predicting and optimizing their interactions with biological targets, which, in turn, influences their therapeutic efficacy, safety, and overall impact on living organisms. Here, we present the first application of competitive enantioselective acylation (CEA) reactions in conjunction with LC/MS analysis for determining the absolute configuration of secondary alcohols in natural products which were purified as a mixture. This approach utilizes the enantiomeric pair of HBTM (homobenzotetramisole) catalysts, demonstrating sufficient kinetic resolution for the acylation of secondary alcohols. The rapid reaction kinetics were quantitatively estimated with LC/MS analysis as the characterization technique for the enantioselective transformations. Our study has expanded the application of the CEA reaction coupled with LC/MS analysis to mixtures. Utilizing LC/MS analysis, the CEA reaction offers a sensitive and simple method for stereochemistry determination. Additionally, the application of the CEA reaction is cost/time-effective since only small quantities of substrates and a short reaction time are required for characterizing the absolute configuration of secondary alcohols in natural products compared to other conventional methods.