Fluoroalkyl N-sulfonyl hydrazones: An efficient reagent for the synthesis of fluoroalkylated compounds

Fluoroalkyl N-sulfonyl hydrazones are versatile reagents that can be used to synthesize a wide range of diverse fluoroalkylated organic molecules. Although it has been known since 1975, the chemistry of fluoroalkyl N-sulfonyl hydrazones has recently only received great attention from the scientific community. Generally, they are used as either safe and bench-stable diazo precursors in carbene transfer reactions or as 1,3-dipoles in cycloaddition and cyclization reactions. Notably, fluoroalkyl N-sulfonyl hydrazones to replace toxic fluoroalkyl diazo compounds in carbene transfer reactions reduce the risk of rapid accumulation of explosive diazo compounds and improve functional group compatibility and substrate scope. Given the growing importance of fluoroalkyl N-sulfonyl hydrazones in chemical synthesis, a comprehensive review of this topic in the literature is essential to demonstrate their synthetic potential. In this review, we critically summarize and comprehensively analyze the publications in various literatures on the chemistry of fluoroalkyl N-sulfonyl hydrazones starting from 1990 to date. The classification of the different reactivity profiles of fluoroalkyl N-sulfonyl hydrazones and the efficiencies of similar types of reactions or substrates with fluoroalkyl diazo compounds are compared.