New Trends in Asymmetric Phase Transfer Catalysis

70 removed from dedication as F. Cozzi turns 72 years this year, the article is however included in the collection webpage, and the related footnote has been added. Phase Transfer Catalysis (PTC) is a powerful tool to perform reactions in a practical fashion, both in laboratory and industrial scale. Significant cost savings and major process improvements can be achieved in reactions performed under PTC conditions. In the last few years remarkable results in stereoselective reactions were achieved using chiral, non-racemic quaternary ammonium salts. Moreover, the use of bulky, chiral phosphate anions paired with achiral cations to generate lipophilic ion pairs allowed to design new avenues for the stereoselective construction of important building blocks. Hydrogen bond interactions were also shown to provide new pathways for asymmetric nucleophilic substitutions using insoluble reagents under PTC conditions. This Review will focus on recent advances in developing practical synthetic routes to construct molecules in a stereoselective fashion under PTC conditions.

Automated summary

This article highlights the efficacy of phase transfer catalysis (PTC) in performing reactions on both laboratory and industrial scales, with significant cost savings and process improvements. It discusses recent advances in stereoselective reactions using chiral, non-racemic quaternary ammonium salts, the use of bulky, chiral phosphate anions paired with achiral cations to generate lipophilic ion pairs, and the application of hydrogen bond interactions in asymmetric nucleophilic substitutions under PTC conditions.