7-Azaindoline Auxiliary: A Versatile Attachment Facilitating EnantioselectiveC-C Bond-Forming Catalysis

Abstract

This short review provides an overview of 7-azaindoline auxiliaries in asymmetric catalysis. 7-Azaindoline serves as a useful attachment to carboxylic acids, and the thus-formed 7-azaindoline amides are amenable to atom-economical C-C bond-forming reactions with high stereoselectivity. The attachment is used for the sake of gaining traction in promoting the reaction of interest and can be easily removed after enantioselective reactions. Both nucleophilic and electrophilic catalyses are realized with broad tolerance for functional groups, showcasing the usefulness of 7-azaindoline auxiliaries for practical and streamlined synthesis of a wide range of acyclic chiral building blocks. 1 Introduction 2 7-Azaindoline as a Key Auxiliary 3 7-Azaindoline Amide as a Pronucleophile 3.1 α-Carbon-Substituted 7-Azaindoline Amide 3.2 α-Nitrogen-Substituted 7-Azaindoline Amide 3.3 α-Oxygen-Substituted 7-Azaindoline Amide 3.4 α-Fluorocarbon-Substituted 7-Azaindoline Amide 3.5 α-Halogen-Substituted 7-Azaindoline Amide 3.6 α-Sulfur-Substituted 7-Azaindoline Amide 4 7-Azaindoline Amide as an Electrophile 4.1 Conjugate Addition of Butenolides 4.2 1,3-Dipolar Cycloaddition of Nitrones 5 Transformation of 7-Azaindoline Amide 6 Conclusion.