Abstract
Non-classical hydrogen bonds (NCHBs) have attracted significant interest in the past decade particularly because of their important role in asymmetric catalytic systems. These weak interactions (< 4 kcal/mol) offer much flexibility in the preorganization of molecular entities required to achieve high enantioselectivity. Herein, we review some recent important organocatalytic asymmetric reactions where a NCHB serves as a critical factor in determining the stereoselectivity.
1 Introduction
2 Hydrogen Bonds (HBs) and Non-Classical Hydrogen Bonds (NCHBs)
3 Early Developments in NCHBs
4 Selected Examples of NCHBs in Organic Transformations
5 Recent Examples of NCHBs in Enantioselective Reactions
6 Conclusions and Outlook