Acid CF*3*-reagent (or termed as Togni Reagent II) is the second commercialized hypervalent iodine CF*3*-reagent. Its main difference from Alcohol-CF*3*-reagent is higher crystallinity and lower solubility in organic solvents at comparable conditions. Generally speaking, polar solvents are preferred for reactions where Acid-CF*3*-reagent is used (typically THF, DCM, MeCN, alcohols, glymes).