Robust Analytical Methods for Monitoring the Formation of a Chiral Oxazaborolidine Catalyst

Abstract

Having robust and reliable methods for monitoring catalyst activation processes is an important part of ensuring the reproducibility of a catalytic reaction. For asymmetric Diels−Alder reactions, chiral oxazaborolidine or oxazaborolidinium catalysts are powerful reagents that promote these reactions in high yield and selectivity. Supported by mechanistic findings, several modern analytical methods are compared for quantitating the oxazaborolidine catalyst formation from amino alcohol and boroxine to arrive at useful monitoring methods for this important transformation.

Precise Control of the Oxidation Reaction in a High-Purity Dexlansoprazole Synthesis Process Using In Situ Infrared

“…In this work, we introduce in situ infrared (IR) spectroscopy − to provide real-time information of reaction processes as a typical example of the process analytical technology. − At first, we optimized the reaction parameters of asymmetric sulfur oxidation in Kagan to obtain the appropriate raw material ratio and reaction conditions. Then, the concentration changes of starting materials, intermediates, and products are monitored by in situ IR spectroscopy in real time, and the end point of the asymmetric sulfur oxidation reaction in Kagan could be easily determined, and the byproducts are traceable.…”

Enantiodivergent Photochemical Rearrangements Due to Different Coordination Modes at an Oxazaborolidine Lewis Acid Catalyst

“…Oxazaborolidines have emerged as versatile chiral catalysts in organic chemistry . They can be readily prepared from 1,2-amino alcohols and a boronic acid which in turn allows to fine-tune their performance by judicious choice of substituents . Ever since their use in the enantioselective reduction of ketones, new applications have been discovered, many of which rely on their Lewis acid character.…”