Asymmetric Cycloetherifications by Bifunctional Aminothiourea Catalysts: The Importance of Hydrogen Bonding

Abstract

Chiral oxacyclic frameworks are prevalent in many natural products and bioactive compounds. In addition, a number of them are important synthetic intermediates. Thus, the synthesis of such structures is a significant goal in the field of organic chemistry. However, the development of catalytic asymmetric cycloetherification for the straightforward synthesis of these compounds remains a challenge. In this study, we propose the use of aminothiourea catalysis as an effective way to accomplish such a challenge. The asymmetric synthesis of chiral oxygen heterocycles, including tetrahydrofurans, tetrahydropyrans, and 1, 3-dioxolanes, is demonstrated herein using intramolecular oxy-Michael addition mediated by bifunctional aminothiourea catalysts.