Triflic Anhydride (Tf2O)-Activated Transformations of Amides, Sulfoxides and Phosphorus Oxides via Nucleophilic Trapping
Jun Yong Kang, Hai Huang
Abstract
Abstract Trifluoromethanesulfonic anhydride (Tf2O) is utilized as a strong electrophilic activator in a wide range of applications in synthetic organic chemistry, leading to the transient generation of a triflate intermediate. This versatile triflate intermediate undergoes nucleophilic trapping with diverse nucleophiles to yield novel compounds. In this review, we describe the features and applications of triflic anhydride in organic synthesis reported in the past decade, especially in amide, sulfoxide, and phosphorus oxide chemistry through electrophilic activation. A plausible mechanistic pathway for each important reaction is also discussed. 1 Introduction 2 Amide Chemistry 2.1 Carbon Nucleophiles 2.2 Hydrogen Nucleophiles 2.3 Nitrogen Nucleophiles 2.4 Oxygen and Sulfur Nucleophiles 2.5 hosphorus Nucleophiles 2.6 A Vilsmeier-Type Reagent 2.7 Umpolung Reactivity in Amides 3 Sulfoxide Chemistry 3.1 Oxygen Nucleophiles 3.2 Carbon Nucleophiles 3.3 Nitrogen Nucleophiles 3.4 Thionium Reagents 4 Phosphorus Chemistry 4.1 Hendrickson’s Reagent 4.2 Diaryl Phosphine Oxides 4.3 Phosphonates, Phosphates and Phosphinates 5 Conclusion and Outlook