Unravelling the Development of Non-Covalent Organocatalysis in India

Abstract This review is devoted to underpinning the contributions of Indian researchers towards asymmetric organocatalysis. More specifically, a comprehensive compilation of reactions mediated by a wide range of non-covalent catalysis is illustrated. A detailed overview of vividly catalogued asymmetric organic transformations promoted by hydrogen bonding and Brønsted acid catalysis, alongside an assortment of catalysts is provided. Although asymmetric organocatalysis has etched itself in history, we aim to showcase the scientific metamorphosis of Indian research from baby steps to large strides within this field. 1 Introduction 2 Non-Covalent Catalysis and Its Various Activation Modes 3 Hydrogen-Bonding Catalysis 3.1 Urea- and Thiourea-Derived Organocatalysts 3.1.1 Thiourea-Derived Organocatalysts 3.1.2 Urea-Derived Organocatalysts 3.2 Squaramide-Derived Organocatalysts 3.2.1 Michael Reactions 3.2.2 C-Alkylation Reactions 3.2.3 Mannich Reactions 3.2.4 [3+2] Cycloaddition Reactions 3.3 Cinchona-Alkaloid-Derived Organocatalysts 3.3.1 Michael Reactions 3.3.2 Aldol Reactions 3.3.3 Friedel–Crafts Reactions 3.3.4 Vinylogous Alkylation of 4-Methylcoumarins 3.3.5 C-Sulfenylation Reactions 3.3.6 Peroxyhemiacetalisation of Isochromans 3.3.7 Diels–Alder Reactions 3.3.8 Cycloaddition Reactions 3.3.9 Morita–Baylis–Hilman Reactions 4 Brønsted Acid Derived Organocatalysts 4.1 Chiral Phosphoric Acid Catalysis 4.1.1 Diels–Alder Reactions 4.1.2 Addition of Ketimines 4.1.3 Annulation of Acyclic Enecarbamates 5 Conclusion