Recent Applications of Triphenylmethyl (Trityl) Cations in Synthesis

Abstract Carbocations, often deemed transient and unstable intermediates in organic chemistry, gained significant recognition with the awarding of the Nobel Prize in Chemistry to George A. Olah in 1995 for his work on carbocation chemistry. The triphenylmethyl (trityl) cation, a stable and versatile carbocation, has emerged as a significant player in organic reactions. This short review provides an update on the use of trityl cations as organic Lewis acids, highlighting their role in various catalytic processes. We aim to offer a comprehensive overview of the latest developments and prospects of these ions. The continued exploration of trityl cations promises to enhance their role as a valuable tool in synthetic chemistry, offering efficient alternatives to traditional inorganic or metal-based catalysts. 1 Introduction 2 Synthesis of Fluorinated Triphenylmethylium Acids 3 Redox Behavior of Tritylium Salts 4 Lewis Acids for Organocatalysis 5 Catalysis of Multicomponent Syntheses 6 Initiation of Carbenium- and Silylium-Centered Reactivity 7 Polymer Synthesis 8 Further Applications of Tritylium Salts 9 Conclusion and Outlook